Methods for generating hybrid analyte level output, and devices and systems related thereto

ABSTRACT

Generally, methods, devices, and systems for generating a hybrid analyte level output are provided. The uncompensated analyte levels lag in time with respect to the lag-compensated analyte levels, and the hybrid analyte level output tracks between the uncompensated analyte levels and the lag-compensated analyte levels according to predetermined criteria.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/077,520 filed Mar. 22, 2016, which is a continuation of U.S. patentapplication Ser. No. 13/538,406 filed Jun. 29, 2012, now U.S. Pat. No.9,289,164 which claims benefit of priority under 35 U.S.C. § 119(e) toU.S. Provisional Patent Application No. 61/503,338 filed Jun. 30, 2011,the disclosures of which are incorporated by reference herein in theirentirety.

BACKGROUND

In many instances it is desirable or necessary to regularly monitor theconcentration of particular constituents in a fluid. A number of systemsare available that analyze the constituents of bodily fluids such asblood, urine and saliva. Examples of such systems conveniently monitorthe level of particular medically significant fluid constituents, suchas, for example, cholesterol, ketones, vitamins, proteins, and variousmetabolites or blood sugars, such as glucose. Diagnosis and managementof patients suffering from diabetes mellitus, a disorder of the pancreaswhere insufficient production of insulin prevents normal regulation ofblood sugar levels, requires carefully monitoring of blood glucoselevels on a daily basis.

In vivo analyte monitoring systems include an in vivo analyte sensor. Atleast a portion of the sensor is positioned beneath the skin surface ofa user to contact bodily fluid (e.g., blood or interstitial fluid (ISF))to monitor one or more analytes in the fluid over a period of time. Thisis also referred to as continuous analyte monitoring in that the sensorremains positioned in the user for a continuous period of time. Otherforms of testing include in vitro testing—e.g., by withdrawing bloodfrom a patient and applying the blood to a test strip for insertion intoan analyte monitoring device, such as a glucose meter.

ISF glucose may lag in time behind blood glucose. That is, if the bloodglucose is falling and reaches a low point, the ISF glucose will reachthat low point some time later, such as 10 minutes for example.Traditionally, the goal of analyte monitoring systems is to provideresults that approximate blood glucose concentrations since bloodglucose concentrations may better represent the glucose level in thepatient's blood.

SUMMARY

Aspects of the present disclosure relate to methods, devices and systemsthat generate a hybrid analyte level output including uncompensatedanalyte levels and lag-compensated analyte levels. The hybrid analytelevel outputs may track the lag-compensated analyte levels at certaintimes, and track uncompensated analyte levels at other times. Variouscriteria (e.g., times, conditions, events, etc.) may be predeterminedand associated with the tracking of lag-compensated analyte levels orthe tracking of uncompensated analyte levels. For example, there may betimes when a lag-compensated signal is more important, such as duringhigh and/or low analyte level reading, or when high rates-of-changeoccur in the analyte levels, etc. Lag-compensation may generally improveaccuracy during high rates-of-change, for instance, because thelag-compensated signal will respond faster than the uncompensated signalto the change. Examples of high glucose rates-of-change may include, butare not limited to, plus or minus 1 mg/dL per hour or greater, includingplus or minus 2 mg/dL per hour, plus or minute 3 mg/dL per hour, etc.For example, criteria may include analyte level thresholds or rangesthat are predetermined and programmed into an analyte monitoring systemand used to determine when a transition should occur from trackinguncompensated to lag-compensated analyte levels, or vice versa. Thevarious analyte thresholds may be different for transitions fromuncompensated to lag-compensated analyte levels and for transitions fromlag-compensated to uncompensated analyte levels.

The methods, devices, and systems may relate to one or more componentsof an analyte monitoring system, such as continuous analyte monitoringsystems, including an in vivo analyte sensor, a sensor electronics unitthat receives analyte sensor data from the in vivo analyte sensor, and areceiver unit that receives analyte sensor data from the sensorelectronics unit. A display may also be included with the sensorelectronics unit or receiver unit. Other components and devices may alsobe implemented in the system, such as medication delivery devices (e.g.,insulin delivery devices), etc.

In some aspects of the present disclosure, methods of generating ahybrid analyte level output are provided. The methods include receivingsensor data which may be in vivo sensor data from an in vivo sensor, andgenerating a hybrid analyte level output including uncompensated analytelevels and lag-compensated analyte levels. The uncompensated analytelevels lag in time with respect to the lag-compensated analyte levels,and the hybrid analyte level output tracks between the uncompensatedanalyte levels and the lag-compensated analyte levels according topredetermined criteria. The term “track”, ‘tracks”, “tracking”, or thelike, is used broadly herein, and may include using the actual signallevels (e.g., by switching between the two, etc.), duplicating orreproducing the signals, calculating the signals, approximating thesignals, imitating or simulating the signals, following or otherwiseresembling the signals, etc. This may also include instances where oneor both of the lag-compensated and uncompensated signal levels arecalculated for the purpose of generating the hybrid output only, and notnecessarily generated as a separate stand-alone signal itself. Incertain embodiments where both the lag-compensated and uncompensatedsignals are generated, the hybrid output may include, for example, usingthe lag-compensated and uncompensated signals or levels by switchingbetween the actual lag-compensated and uncompensated signals to form thehybrid output—e.g., displaying the generated uncompensated signal whentracking the uncompensated signal, and displaying the lag-compensatedsignal when tracking the lag-compensated signal. In certain embodiments,the hybrid output signal may include generating a signal thatreproduces, approximates, simulates, calculates, etc., thelag-compensated and uncompensated signals, and then the generated hybridanalyte output signal is outputted on display. In some instances, forexample, the hybrid analyte level output may be generated from anuncompensated signal, to which lag-compensation may be activated anddeactivated.

In some aspects of the present disclosure, analyte monitoring devicesare provided. The analyte monitoring devices include a processor andmemory operably coupled to the processor. The memory includesinstructions stored therein to generate a hybrid analyte level output.The instructions include instructions for receiving sensor data whichmay be generated from an in vivo sensor, and instructions for generatinga hybrid analyte level output including uncompensated analyte levels andlag-compensated analyte levels. The uncompensated analyte levels lag intime with respect to the lag-compensated analyte levels, and the hybridanalyte level output tracks between the uncompensated analyte levels andthe lag-compensated analyte levels according to predetermined criteria.

In some aspects of the present disclosure, analyte monitoring systemsare provided. The analyte monitoring systems include an analyte sensorwhich may be an in vivo sensor, an analyte monitoring device incommunication with the analyte sensor, a processor, and memory operablycoupled to the processor. The memory includes instructions storedtherein to generate a hybrid analyte level output. The instructionsinclude instructions for receiving sensor data which may be in vivosensor data from an in vivo sensor, instructions for calculatinguncompensated analyte levels based on the sensor data, and instructionsfor generating a hybrid analyte level output including the uncompensatedanalyte levels and lag-compensated analyte levels. The uncompensatedanalyte levels lag in time with respect to the lag-compensated analytelevels, and the hybrid analyte level output tracks between theuncompensated analyte levels and the lag-compensated analyte levelsaccording to predetermined criteria.

INCORPORATION BY REFERENCE

The following patents, applications and/or publications are incorporatedherein by reference for all purposes: U.S. Pat. Nos. 7,041,468;5,356,786; 6,175,752; 6,560,471; 5,262,035; 6,881,551; 6,121,009;7,167,818; 6,270,455; 6,161,095; 5,918,603; 6,144,837; 5,601,435;5,822,715; 5,899,855; 6,071,391; 6,120,676; 6,143,164; 6,299,757;6,338,790; 6,377,894; 6,600,997; 6,773,671; 6,514,460; 6,592,745;5,628,890; 5,820,551; 6,736,957; 4,545,382; 4,711,245; 5,509,410;6,540,891; 6,730,200; 6,764,581; 6,299,757; 6,461,496; 6,503,381;6,591,125; 6,616,819; 6,618,934; 6,676,816; 6,749,740; 6,893,545;6,942,518; 6,514,718; 5,264,014; 5,262,305; 5,320,715; 5,593,852;6,746,582; 6,284,478; 7,299,082; U.S. Patent Application No. 61/149,639,entitled “Compact On-Body Physiological Monitoring Device and MethodsThereof”, U.S. patent application Ser. No. 11/461,725, filed Aug. 1,2006, entitled “Analyte Sensors and Methods”; U.S. patent applicationSer. No. 12/495,709, filed Jun. 30, 2009, entitled “Extruded ElectrodeStructures and Methods of Using Same”; U.S. Patent ApplicationPublication No. US2004/0186365; U.S. Patent Application Publication No.2007/0095661; U.S. Patent Application Publication No. 2006/0091006; U.S.Patent Application Publication No. 2006/0025662; U.S. Patent ApplicationPublication No. 2008/0267823; U.S. Patent Application Publication No.2007/0108048; U.S. Patent Application Publication No. 2008/0102441; U.S.Patent Application Publication No. 2008/0066305; U.S. Patent ApplicationPublication No. 2007/0199818; U.S. Patent Application Publication No.2008/0148873; U.S. Patent Application Publication No. 2007/0068807; USpatent Application Publication No. 2010/0198034; US patent ApplicationPublication No. 2008/0081977; US patent Application Publication No.2009/0198118; and US provisional application No. 61/149,639 titled“Compact On-Body Physiological Monitoring Device and Methods Thereof”,the disclosures of each of which are incorporated herein by reference intheir entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of various embodiments of the present disclosureis provided herein with reference to the accompanying drawings, whichare briefly described below. The drawings are illustrative and are notnecessarily drawn to scale. The drawings illustrate various embodimentsof the present disclosure and may illustrate one or more embodiment(s)or example(s) of the present disclosure in whole or in part. A referencenumeral, letter, and/or symbol that is used in one drawing to refer to aparticular element may be used in another drawing to refer to a likeelement.

FIG. 1 illustrates a chart simultaneously displaying an uncompensatedanalyte level and a lag-compensated analyte level tracked over time fora patient.

FIG. 2 illustrates a flowchart of a method for generating a hybridanalyte level output, according to one embodiment.

FIG. 3 illustrates a chart of a hybrid analyte level output, accordingto one embodiment.

FIG. 4 illustrates a flowchart for a method of generating a hybridanalyte level output, according to one embodiment.

FIG. 5 illustrates a flowchart for a method of generating a hybridanalyte level output, according to one embodiment.

FIG. 6A illustrates a chart of a hybrid output as it transitions fromlag-compensated analyte levels to uncompensated analyte levels,according to one embodiment.

FIG. 6B illustrates a chart of a hybrid output as it transitions fromlag-compensated analyte levels to uncompensated analyte levels,according to one embodiment.

FIG. 7A illustrates a chart of a hybrid output as it transitions fromlag-compensated analyte levels to uncompensated analyte levels,according to one embodiment.

FIG. 7B illustrates a chart of a hybrid output as it transitions fromlag-compensated analyte levels to uncompensated analyte levels,according to one embodiment.

FIG. 8A illustrates a chart of a hybrid output as it transitions fromuncompensated analyte levels to lag-compensated analyte levels,according to one embodiment.

FIG. 8B illustrates a chart of a hybrid output as it transitions fromuncompensated analyte levels to lag-compensated analyte levels,according to one embodiment.

FIG. 9A illustrates a chart of a hybrid output as it transitions fromuncompensated analyte levels to lag-compensated analyte levels,according to one embodiment.

FIG. 9B illustrates a chart of a hybrid output as it transitions fromuncompensated analyte levels to lag-compensated analyte levels,according to one embodiment.

FIG. 10 illustrates a flowchart for a method of generating a hybridanalyte level output, according to one embodiment.

FIG. 11 shows an analyte monitoring system, according to one embodiment.

FIG. 12 is a block diagram of the data processing unit shown in FIG. 11,according to one embodiment.

FIG. 13 is a block diagram of an embodiment of a receiver/monitor unitsuch as the primary receiver unit of the analyte monitoring system shownin FIG. 11, according to one embodiment.

DETAILED DESCRIPTION

Before the embodiments of the present disclosure are described, it is tobe understood that the present disclosure is not limited to particularembodiments described, as such may, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting, since the scope of the embodiments of the present disclosurewill be limited only by the appended claims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassedwithin the present disclosure. The upper and lower limits of thesesmaller ranges may independently be included or excluded in the range,and each range where either, neither or both limits are included in thesmaller ranges is also encompassed within the present disclosure,subject to any specifically excluded limit in the stated range. Wherethe stated range includes one or both of the limits, ranges excludingeither or both of those included limits are also included in the presentdisclosure.

In the description of the present disclosure herein, it will beunderstood that a word appearing in the singular encompasses its pluralcounterpart, and a word appearing in the plural encompasses its singularcounterpart, unless implicitly or explicitly understood or statedotherwise. Merely by way of example, reference to “an” or “the”“analyte” encompasses a single analyte, as well as a combination and/ormixture of two or more different analytes, reference to “a” or “the”“concentration value” encompasses a single concentration value, as wellas two or more concentration values, and the like, unless implicitly orexplicitly understood or stated otherwise. Further, it will beunderstood that for any given component described herein, any of thepossible candidates or alternatives listed for that component, maygenerally be used individually or in combination with one another,unless implicitly or explicitly understood or stated otherwise.Additionally, it will be understood that any list of such candidates oralternatives, is merely illustrative, not limiting, unless implicitly orexplicitly understood or stated otherwise.

Various terms are described below to facilitate an understanding of thepresent disclosure. It will be understood that a correspondingdescription of these various terms applies to corresponding linguisticor grammatical variations or forms of these various terms. It will alsobe understood that the present disclosure is not limited to theterminology used herein, or the descriptions thereof, for thedescription of particular embodiments. Merely by way of example, thepresent disclosure is not limited to particular analytes, bodily ortissue fluids, blood or capillary blood, or sensor constructs or usages,unless implicitly or explicitly understood or stated otherwise, as suchmay vary. The publications discussed herein are provided solely fortheir disclosure prior to the filing date of the application. Nothingherein is to be construed as an admission that the embodiments of thepresent disclosure are not entitled to antedate such publication byvirtue of prior invention. Further, the dates of publication providedmay be different from the actual publication dates which may need to beindependently confirmed.

The term “processor” is used broadly herein, and may include any type ofprogrammable or non-programmable processing device, such as amicroprocessor, microcontroller, application-specific integratedcircuits (ASICS), programmable logic devices (PLDs), field-programmablegate arrays (FPGAs), etc. The term “processor” may also include multipleprocessing devices working in conjunction with one another.

As summarized above, in some aspects of the present disclosure, methods,devices, and systems related to generating a hybrid analyte level outputare provided. The hybrid analyte level output includes bothuncompensated analyte levels and lag-compensated analyte levels that arebased off sensor data derived from an in vivo positioned analyte sensor.Predetermined criteria may be used to determine when the hybrid analytelevel output tracks uncompensated analyte levels or lag-compensatedanalyte levels.

Glucose levels taken from interstitial fluid (ISF) lag in time behindblood glucose levels. Lag-compensation techniques may be used tolag-compensate the ISF analyte levels to more closely approximate bloodglucose levels. In this way, uncompensated analyte levels (e.g., ISFanalyte level) may be lag-compensated (e.g., by applying alag-compensation filter) to generate a lag-compensated analyte levels(e.g., an approximation of blood glucose levels).

In some circumstances, however, an ISF analyte level may be moreappropriate or desirable. For example, ISF glucose may be morerepresentative of how a person feels—e.g., during hypoglycemia orhyperglycemia or when approaching hypo- or hyper- glycemia. Thus, if apatient's blood glucose level rises after being hypoglycemic, thepatient may falsely assume they are “safe” when in actuality their ISFglucose level is lagging and may still be low.

Blood glucose levels, however, may be more appropriate or desirable. Forexample, blood glucose levels may act as a precursor to where the ISFglucose will eventually be, and are therefore useful in other scenarios.For instances, as glucose levels are falling to a low value, a patientthat gets a low blood glucose reading may know ahead of time that theywill soon start feeling unwell, as their ISF glucose later gets low.

In some aspects of the present disclosure, hybrid analyte level outputs(also referred to herein as “hybrid output”) are provided that includeuncompensated analyte levels (e.g., ISF glucose levels) andlag-compensated analyte levels (e.g., approximations of blood glucose,also referred to hereafter as “blood glucose”, achieved bylag-compensation techniques).

The hybrid outputs may include uncompensated analyte levels andlag-compensated analyte levels in various manners, as will bedemonstrated and described herein. For example, in one embodiment, ahybrid analyte level output may be designed to track uncompensatedanalyte levels (e.g., ISF glucose levels) when the glucose is low andrising; otherwise, the hybrid output tracks blood glucose (e.g.,approximations of blood glucose achieved by lag-compensationtechniques). The transitions between uncompensated analyte levels andlag-compensated analyte levels may, for instance, be made smooth byimplementing a smoothing function, such as a weighted combination of theuncompensated analyte levels and lag-compensated analyte levels. Theembodiments provided in the following paragraphs are exemplary and thescope of the present disclosure should not be construed as limited tothe exemplary embodiments. Further, the features described in oneembodiment may be equally applicable in another embodiment.

FIG. 1 illustrates a chart simultaneously displaying an uncompensatedanalyte level (e.g., ISF glucose level) and a lag-compensated analytelevel (e.g., approximation of blood glucose level) tracked over time fora patient. The chart illustrates that ISF glucose level lags the bloodglucose level. The glucose value is represented on one axis and timerepresented on the other axis. The blood glucose and ISF glucose areshown as a solid line and dotted line, respectively. Before time T1, thepatient's glucose level is approximately constant and thus the bloodglucose and the ISF glucose are approximately the same value. When thepatient's blood glucose level drops at time T1, the ISF glucose lagsbehind and drops after some time period of delay after the bloodglucose.

Thus, for example, when the blood glucose drops to the low thresholdline shown in the chart, as represented at time T2, the ISF glucose isstill at a higher glucose value than the threshold value and will reachthe threshold line after some delay in time. At time T3, the patient'sblood glucose level flattens out and begins to rise again. As the ISFglucose is lagging the blood glucose, the ISF glucose is still trendingdownward and will flatten out and rise after a certain delay in time.

At time T4, the blood glucose reaches the threshold line with the ISFglucose still lagging and at a lower glucose value than the thresholdvalue. The ISF glucose reaches the threshold line at time T5, after somedelay in time from when the blood glucose reaches the threshold line.

FIG. 2 illustrates a flowchart of a method for generating a hybridanalyte level output, according to one embodiment. At block 105, sensordata is received. The sensor data may be originally derived from atranscutaneously positioned sensor that communicates the sensor data toan analyte monitoring device. The analyte monitoring device may includeany data processing device that is used to monitor analytes. Forexample, the analyte monitoring device may include, but is not limitedto, a glucose meter, personal computer, a portable computer including alaptop or a handheld device such as a consumer electronic device (e.g.,a personal digital assistant (PDA), a telephone including a cellularphone (e.g., a multimedia and Internet-enabled mobile phone including aniPhone™, a Blackberry®, or similar phone), an mp3 player (e.g., aniPOD™, etc.), a pager, and the like), and/or a drug delivery device(e.g., a medication delivery pump). The analyte monitoring device may,for example, include software necessary to perform the analytemonitoring techniques described herein. The analyte monitoring devicemay receive sensor data originating from the in vivo positioned sensoreither directly or via another data processing device.

In one embodiment, the in vivo positioned sensor is positioned ininterstitial fluid such that a sensing portion resides below the skinand an electrical contact portion resides above (i.e.,transcutaneously), and provides sensor data continuously to the analytemonitoring device (e.g., such as in continuous glucose monitoring (CGM)systems). In another embodiment, the in vivo sensor may provide sensordata upon interrogation by a hand-held unit (e.g., such asintermittently or periodically interrogated analyte sensing systems),for example using radio frequency identification technologies or thelike.

At block 110, uncompensated analyte levels are calculated from thesensor data. For example, a processor on the analyte monitoring devicemay receive sensor data and calculate an uncompensated analyte levelfrom the sensor data. In such case, the sensor data is raw sensor dataacquired by the analyte sensor, for example as current, voltage, or thelike.

In another embodiment, the sensor data that is received in block 105includes the uncompensated analyte level, and thus block 110 is notincluded. For instance, an analyte sensor positioned in interstitialfluid may generate raw sensor data, and further include electroniccircuitry to calculate the uncompensated analyte level and transmit itto an analyte monitoring device as sensor data. The analyte monitoringdevice receives the sensor data including the uncompensated analytelevel and generates the hybrid analyte level output.

At block 115, a hybrid analyte level output is generated that includesuncompensated analyte levels and lag-compensated analyte levels.Uncompensated analyte levels calculated from sensor data derived frominterstitial fluid will lag in time with respect to the actual analytelevel of the blood. In order to more closely approximate the analytelevel of the blood, the uncompensated analyte level may be lagcompensated (e.g., by applying a lag-compensation filter to theuncompensated analyte level), resulting in a lag-compensated analytelevel. Thus, the uncompensated analyte levels lag in time with respectto the lag-compensated analyte levels.

The hybrid analyte level output tracks between the uncompensated analytelevels and the lag-compensated analyte levels according to predeterminedcriteria. The predetermined criteria may include criteria thatspecifically define when the hybrid analyte level output tracks theuncompensated analyte levels and the lag-compensated analyte levels.This determination may be made, for example, by the processor of theanalyte monitoring device mentioned above. When the processor determinesthat the predetermined criteria for tracking uncompensated analytelevels are met, the hybrid analyte level output will track uncompensatedanalyte levels. When the processor determines that the predeterminedcriteria for tracking lag-compensated analyte levels are met, the hybridanalyte level output will track lag-compensated analyte levels.

FIG. 3 illustrates a chart of a hybrid analyte level output, accordingto one embodiment. The hybrid analyte level output tracks between theuncompensated analyte level (e.g., ISF glucose level) and thelag-compensated analyte level (e.g., approximation of blood glucoselevel) according to predetermined criteria, which will be described infurther detail later. As shown, the exemplary hybrid analyte leveloutput begins tracking the lag-compensated analyte level and continuesto track the lag-compensated analyte level until predetermined criteriaare met for switching to the uncompensated analyte level, as representedat point P1. Thereafter, the hybrid output will track the uncompensatedanalyte levels until predetermined criteria are met for tracking thelag-compensated analyte levels, as represented at point P2.

In the example shown, smoothing functions are implemented at eachtransition between lag-compensated analyte levels and uncompensatedanalyte levels. The smoothing function may, for example, includeweighted combinations of the lag-compensated analyte levels anduncompensated analyte levels at these transition points, such that thehybrid analyte level output includes both the lag-compensated analytelevels and uncompensated analyte levels which are weighted in aparticular manner. For instance, the weighting of the lag-compensatedanalyte levels and uncompensated analyte levels varies over time duringthe transition. For example, transitioning form lag-compensated analytelevels to uncompensated analyte levels may begin with a one hundredpercent weighting on the lag-compensated analyte levels and zero percentweighting on the uncompensated analyte levels; then, over the durationof the transition period, decreasing the weighting on thelag-compensated analyte levels while increasing the weighting on theuncompensated analyte levels; and finally ending the transition withzero percent weighting on the lag-compensated analyte levels and onehundred percent weighting on the uncompensated analyte levels. A similarweighting scheme may apply to transition from uncompensated analytelevels to lag-compensated analyte levels, such that the weighting on theuncompensated analyte levels begins at one hundred percent and decreasesto zero percent while the weighting on the lag-compensated analytelevels begins at zero percent and increases to one hundred percent.Instantaneous jumps and large breaks between the lag-compensated analytelevels and uncompensated analyte levels are thus avoided. For example,at point P1, predetermined criteria are met for switching to theuncompensated analyte level. At this point, a smoothing function (e.g.,which incorporates weighted combinations of the uncompensated andlag-compensated analyte levels) is implemented for the transition fromlag-compensated analyte levels to uncompensated analyte levels, and thehybrid output smoothly switches from the lag-compensated analyte levelsto the uncompensated analyte levels. In different embodiments, smoothingfunctions, such as ones using weighted combinations, may be implementedat one or both transition points, and further, may implement the same ordifferent smoothing functions at the two transitions points.

FIG. 4 illustrates a flowchart for a method of generating a hybridanalyte level output, according to one embodiment. In some instances,such as with CGM systems and intermittent or periodic interrogationanalyte sensing systems, sensor data continues to be received over time.The method shown in FIG. 4 illustrates one cycle that may be repeated asnew sensor data is continuously acquired over time from an in vivopositioned sensor and transmitted to a receiver, for example. Tofacilitate explanation, the method FIG. 4 is described with reference toa cycle of operations at time, t(1). The next cycle would be at time,t(2); and the next cycle at time, t(3); and so on for t(n) cycles.Moreover, the previous cycle would be at time, t(0).

At block 405, sensor data is received. For example, the sensor data maybe originally derived from a transcutaneously positioned sensor thatcommunicates the sensor data to an analyte monitoring device, such asdescribed above. For example, at least a portion of an in vivo sensormay be positioned in interstitial fluid and provide sensor datacontinuously and automatically to the analyte monitoring device (e.g.,such as in CGM systems). In another embodiment, the in vivo positionedsensor may provide sensor upon interrogation by a hand held device(e.g., such intermittent or periodic interrogation analyte sensingsystems). The sensor data may be “raw”, meaning that it would need to beprocessed to represent the analyte level. For instance, the raw sensordata may need to be multiplied by a conversion factor to represent ananalyte level. Furthermore, an analyte level may be determined,sometimes in the form of a filter, from the most recently receivedsensor data in conjunction with one or more historical sensor dataretrieved from memory.

At block 410, an uncompensated analyte level is calculated from thesensor data. For example, a processor on the analyte monitoring devicemay receive sensor data periodically and calculate the uncompensatedanalyte level from the sensor data. In one embodiment, the analytemonitoring device may include an electronic sensor control unit havingthe processor and electrically coupled to an in vivo positioned sensor,for example. The processor receives the sensor data derived from the invivo positioned sensor, for instance. In another embodiment, the analytemonitoring device may include a receiver having a processor andcommunicably coupled to an electronic sensor control unit that iscoupled to an in vivo positioned sensor. For instance, the sensorcontrol unit transmits sensor data derived from the in vivo positionedsensor to the receiver, and ultimately the processor within thereceiver.

In another embodiment, the sensor data that is received in block 405includes the uncompensated analyte level, and thus block 410 is notincluded. For instance, an analyte sensor positioned in interstitialfluid may generate raw sensor data, and further include electroniccircuitry to calculate the uncompensated analyte level and transmit itto an analyte monitoring device as sensor data. The analyte monitoringdevice receives the sensor data including the uncompensated analytelevel and generates the hybrid analyte level output.

At block 415, a selected analyte level is compared to predeterminedcriteria to determine whether the hybrid output should trackuncompensated analyte levels or lag-compensated analyte levels. Anyvariety of sources may be used as the selected analyte level. Forinstance, example sources may include, but are not limited to,lag-compensated analyte levels, uncompensated analyte levels, hybridoutputs, etc. Furthermore, the selected analyte level may apply to aspecific occurrence of those analyte levels, such as the most recentlygenerated analyte level. For example, in certain instances, the selectedanalyte level may be the most recently generated uncompensated analytelevel, or the most recently generated lag-compensated analyte level. Inother instances, the selected analyte level may be the most recentlygenerated hybrid output.

The term “most recently” and “most recent” and the like refer to thelast occurrence. For example, when at block 415, the most recentlycalculated uncompensated analyte level would refer to the levelcalculated at block 410 in the current cycle at time, t(1); the mostrecently generated lag-compensated analyte level would refer to thelevel calculated at block 425 in the previous cycle at time, t(0), themost recently generated hybrid output would refer to the levelcalculated at either blocks 445 or 470 in the previous cycle at time,t(0). In another embodiment, the transitional output levels (e.g.,weighted combinations of uncompensated analyte levels andlag-compensated analyte levels) of the hybrid output may also be used asthe selected analyte level, and thus the most recently generated hybridoutput may also refer to the analyte levels calculated at either blocks435 or 460 in the previous cycle at time, t(0).

One or more sources may be used as a selected analyte level in differentcircumstances in an embodiment. In one embodiment, only one source maybe used at all times. For example, in one embodiment, the selectedanalyte level may always be the most recently calculated uncompensatedanalyte level. In another embodiment, the selected analyte level mayalways be the most recent lag-compensated analyte level. In yet anotherembodiment, the selected analyte level may always be the most recentlygenerated analyte level for the hybrid output. The term “selected” isused broadly herein and may include a selection from multiple sources ifmultiple sources are implemented, or a selection of a single source thatis used at all times.

In one embodiment, the selected analyte level that is used may vary fromcycle to cycle. For example, the selected analyte level may depend onfactors from the current cycle, previous cycle, etc. For instance, theselected analyte level may be selected based on whether the mostrecently generated hybrid output was an uncompensated or lag-compensatedanalyte level; or whether the hybrid output is transitioning. Theselected analyte level may be selected based on a variety of factors,such as, but not limited to, the analyte rate-of-change, direction ofanalyte rate-of-change, acceleration of the rate, analyte level (e.g.,above or below a threshold value), durations of time, etc. A variety ofpermutations and combinations of one or more of the variouscircumstances and factors may be implemented in various embodiments.Some exemplary selection schemes are described in further detail later.

The predetermined criteria may include criteria for trackinguncompensated analyte levels, for example. When this criteria is met,the hybrid output will track the uncompensated analyte levels. Thepredetermined criteria may also include criteria for trackinglag-compensated analyte levels. When this criteria is met, the hybridoutput will track the lag-compensated analyte levels. For example, thelag-compensated analyte level may be generated by applying alag-compensation filter to the uncompensated analyte level.

In one embodiment, the criteria for tracking uncompensated analytelevels are the negative of the criteria for tracking lag-compensatedanalyte levels. In other words, if the criteria for trackinguncompensated analyte levels are not met, then the criteria for trackingthe lag-compensated analyte levels are met. For example, in oneembodiment, the predetermined criteria include criteria for tracking theuncompensated analyte levels when selected analyte levels are below apredetermined threshold and have been rising for a predeterminedduration of time. When this criteria is not met (i.e., selected analytelevels are not below a predetermined threshold or have not been risingfor a predetermined duration of time), then the hybrid output tracks thelag-compensated analyte levels.

In another embodiment, the criteria for tracking lag-compensated analytelevels may not necessarily be the negative of the uncompensated analytelevels, as will be described in further detail later. For example,separate and different criteria may be defined for switching in eachdirection.

At block 420, it is determined whether criteria are met for trackinguncompensated analyte levels or lag-compensated analyte levels. Ifcriteria for tracking lag-compensated analyte levels are met, then theuncompensated analyte level is lag compensated (e.g., by applying a lagcompensation filter to the uncompensated analyte level) to generate thelag-compensated analyte level, as represented by block 425. Thelag-compensated analyte level is then used for the hybrid output, asrepresented by block 445. The hybrid output may be output audibly orvisually for the user—e.g., via a speaker or display on the analytemonitoring device—as represented by block 450. This may includeoutputting the hybrid output both audibly and visually in someinstances.

In one embodiment, a smoothing function may be implemented betweentransitions from uncompensated analyte levels to lag-compensated analytelevels, as represented by blocks 430, 435, and 440. At block 430, adetermination is made as to whether the hybrid output is transitioningfrom uncompensated analyte levels. If it is determined that the hybridoutput is not transitioning, then the hybrid analyte level output tracksthe lag-compensated analyte level as shown in block 445. For example, ifthe hybrid output was previously tracking the lag-compensated analytelevel, then it will be determined that the hybrid output is nottransitioning from uncompensated analyte levels to lag-compensatedanalyte levels. The transitioning period may vary in length or time indifferent embodiments.

However, if it is determined at block 430 that the hybrid output istransitioning from uncompensated analyte levels (e.g., the hybrid outputhas been tracking uncompensated analyte levels, or is at a transitionalvalue during the transition process from uncompensated analyte levels tolag-compensated analyte levels), then a smoothing function will beimplemented (or continued to be implemented). For example, at block 435,a weighted combination of the uncompensated analyte level and alag-compensated analyte level is used to generate the hybrid output. Theweighted combination may vary over the transition period—e.g., such thatthe weighting of the lag-compensated analyte levels and theuncompensated analyte levels vary throughout the duration of thetransition period. The hybrid output may then be output audibly orvisually via a speaker or display, as represented by block 440.

Referring back to block 420, if it is determined that the criteria fortracking uncompensated analyte levels are met, then the uncompensatedanalyte level is used for the hybrid output, thus making the hybridoutput track the uncompensated analyte level, as represented by block470. The hybrid output may then be output audibly or visually for theuser—e.g., via a speaker or display on the analyte monitoring device—asrepresented by the block 475. Again, this may include outputting thehybrid output both audibly and visually in some instances.

In one embodiment, a smoothing function may be implemented betweentransitions to uncompensated analyte levels from lag-compensated analytelevels, as represented by blocks 455, 460, and 465. At block 455, it isdetermined whether the hybrid output is transitioning from uncompensatedanalyte levels. If it is determined that the hybrid output is nottransitioning, then the hybrid analyte level output tracks theuncompensated analyte level, as shown in block 470. For example, if thehybrid output was previously tracking the uncompensated analyte level,then it will be determined that the hybrid output is not transitioningfrom lag-compensated analyte levels to uncompensated analyte levels. Thetransitioning period may vary in length or time in differentembodiments.

However, if it is determined at block 455 that the hybrid output istransitioning from lag-compensated analyte levels (e.g., the hybridoutput has been tracking lag-compensated analyte levels, or is at atransitional value during the transition process from lag-compensatedanalyte levels to uncompensated analyte levels), then a smoothingfunction will be implemented (or continued to be implemented). Forexample, at block 460, a weighted combination of the uncompensatedanalyte level and a lag-compensated analyte level is used to generatethe hybrid output. A lag-compensated filter is applied to theuncompensated analyte level at block 460 to generate the lag-compensatedanalyte level for the weighted combination. The hybrid output may thenbe output audibly or visually via a speaker or display, as representedby block 465. The cycle may then be repeated for time, t(2), asrepresented by the arrows returning to box 405 from boxes 440, 445, 465,and 475.

In another embodiment the lag-compensation may be performed at adifferent time than shown in FIG. 4. For example, in one embodiment, thelag-compensation filter is applied to the uncompensated analyte levelafter block 410 and before the comparison to the predetermined criteriaat block 415. In this embodiment, a lag-compensated analyte level isgenerated for each cycle whether or not the hybrid output is determinedto track uncompensated analyte levels or lag-compensated analyte levels.In such case, the lag-compensated analyte level generated may be usedwhen the hybrid output tracks the lag-compensated analyte level (e.g.,block 445) and when the weighted combinations are generated (e.g.,blocks 435 and 460).

In some aspects, another signal may be presented on the user interfaceinstead of the hybrid output signal, or in addition to the hybrid outputsignal. For example, in certain embodiments, the lag-compensated analytelevel is provided on the user interface instead of the hybrid output.The hybrid output may be used, however, to drive a “low analyte level”(e.g., low glucose level) indicator on the user interface according topredetermined criteria. For example, a predetermined low analytethreshold (e.g., low glucose threshold) may be implemented, such thatwhen the hybrid signal drops below the low analyte threshold, theindicator is asserted and presented to the user. For instance, in FIG.3, the lag-compensated signal would be displayed on the display, andonce the hybrid analyte level output dropped below the “low threshold”,the “low analyte level” indicator is initiated and displayed on thedisplay of the device. The low analyte threshold is also referred toherein as the “low-entering analyte threshold” to distinguish it fromthe “low-exiting analyte threshold”, which may or may not be the samethreshold value.

The indicator continues to be asserted until predetermined criteria aremet—e.g., until the hybrid signal crosses above the “low threshold”described above. Other predetermined criteria may be defined. Forexample, the indicator may be unasserted when the hybrid signal crossesanother predetermined “low-exiting analyte threshold” rather than thesame “low threshold described above; when another signal (e.g.,lag-compensated analyte level, uncompensated analyte signal, transitionsignal, etc.) crosses a predetermined low-exiting analyte threshold;etc. For instance, in another embodiment, the indicator continues to beasserted until the uncompensated level crosses above the threshold (see,e.g., T5 in FIG. 1). In this case, the generation of the hybrid signalis optional, and the weighted sum transition method is optional.

For example, in one embodiment, when the lag-compensated analyte levels(e.g., blood glucose levels) are displayed to the user, and when thelag-compensated analyte levels drop below a “low threshold” value, theindicator is asserted. When the uncompensated analyte levels (e.g.,interstitial fluid glucose levels) crosses above the same threshold (oranother predetermined low-exiting threshold), then the indicator isunasserted—e.g., until again asserted. In this way, the users see thelag-compensated glucose level, for example, but the low glucoseindicator stays active for some time after the lag-compensated glucosecrosses above the low glucose threshold (or other low-exiting glucosethreshold if implemented).

In other embodiments, other signals (e.g., uncompensated analytesignals, transitions signals, hybrid output signal, etc.) may also bepresented to the user instead of, or in addition to, the lag-compensatedanalyte signal as described above. Moreover, other signals (e.g.,uncompensated analyte signal, lag-compensated analyte signal, etc.) maybe used to drive a “low analyte level” (e.g., low glucose level)indicator on the user interface. Various combinations may be implementedin other embodiments based on the specific application, therapeuticpurpose, etc.

Again the user interface may be, for example, a display and/or speakeron the analyte monitoring device. Any variety of indicators may beused—e.g., symbols, icons, text, graphical elements, gifs, video clips,etc.— and should represent to the user that the analyte level is low.For instance, examples of the indicator may include, but are not limitedto, visual texts such as, “Warning-low glucose”, “low glucose”, “low”,etc. An indicator may be visual, audible, and/or vibratory, for example.

FIG. 5 illustrates a flowchart for a method of generating a hybridanalyte level output, according to one embodiment. Again, in someinstances, such as with CGM systems and intermittent or periodicinterrogation analyte sensing systems, sensor data continues to bereceived over time. The method shown in FIG. 5 illustrates one cyclethat may be repeated as new sensor data is acquired. To facilitateexplanation, FIG. 5 is described with reference to a cycle of operationsat time, t(1). The next cycle would be at time, t(2); and the next cycleat time, t(3); and so on for t(n) cycles. Moreover, the previous cyclewould be at time, t(0).

At block 505, sensor data is received. For example, the sensor data maybe originally derived from a transcutaneously positioned sensor thatcommunicates the sensor data to an analyte monitoring device. Thepositioned sensor is positioned in interstitial fluid and providessensor data continuously to the analyte monitoring device (e.g., such asin CGM systems). In another embodiment, the positioned sensor mayprovide sensor upon interrogation by a held device (e.g., such as inintermittent or periodic interrogation analyte sensing systems).

At block 510, an uncompensated analyte level is calculated from thesensor data. For example, a processor on the analyte monitoring devicemay receive sensor data and calculate the uncompensated analyte levelfrom the sensor data.

In another embodiment, the sensor data that is received in block 505includes the uncompensated analyte level, and thus block 510 is notincluded. For instance, an analyte sensor positioned in interstitialfluid may generate raw sensor data, and further include electroniccircuitry to calculate the uncompensated analyte level and transmit itto an analyte monitoring device as sensor data. The analyte monitoringdevice receives the sensor data including the uncompensated analytelevel and generates the hybrid analyte level output.

In the embodiment shown in FIG. 5, the predetermined criteria includescriteria for tracking uncompensated analyte levels when selected analytelevels are below a predetermined threshold and have been rising for apredetermined duration of time, as represented by blocks 515 and 520.For this exemplary embodiment, the most recently generatedlag-compensated analyte level is used as the selected analyte level todetermine if the predetermined criteria are met.

When both of these two criteria are met (i.e., the selected analytelevel is below a predetermined threshold and has been rising for apredetermined duration of time), the hybrid output tracks theuncompensated analyte levels. When either of these criteria are not met(i.e., selected analyte level is not below a predetermined threshold orhas not been rising for a predetermined duration of time), the hybridoutput tracks the lag-compensated analyte levels.

For example, at block 515, the selected analyte level is compared to athreshold value. The threshold value may, for instance, be a value thatindicates hypoglycemia or other low glucose value. The most recentlygenerated lag-compensated analyte level would be the lag-compensatedanalyte level that was generated in the previous cycle at time, t(0), atblock 525.

If the selected analyte level (i.e., most recently generatedlag-compensated analyte level) is not below the threshold value, thenthe criteria for tracking uncompensated analyte levels is not met andthe hybrid output determined to track the lag-compensated analytelevels. A lag-compensation filter is then applied to the uncompensatedanalyte level to generate a lag-compensated analyte level, asrepresented by block 525.

If at block 515, the selected analyte level is below the thresholdvalue, then it is determined whether the selected analyte level (i.e.,most recently generated lag-compensated analyte level) has been risingfor a predetermined duration of time, as represented at block 520. Ifthe most recently generated lag-compensated analyte level has not beenrising for a predetermined duration, then the criteria for trackinguncompensated analyte levels is not met and the hybrid output determinedto track the lag-compensated analyte levels. A lag-compensation filteris then applied to the uncompensated analyte level to generate alag-compensated analyte level, as represented by block 525.

After a lag-compensated analyte level is generated at block 525, it isdetermined whether the hybrid output is transitioning from uncompensatedanalyte levels to lag-compensated analyte levels, as represented byblock 530. If it is determined that the hybrid output is nottransitioning, then the hybrid analyte level output tracks thelag-compensated analyte level, as represented by block 545. For example,if the hybrid output was tracking a lag-compensated analyte level attime, t(0), then it will be determined that the hybrid output is nottransitioning from uncompensated analyte levels to lag-compensatedanalyte levels. The hybrid output is then output audibly or visually forthe user—e.g., via a speaker or display on the analyte monitoringdevice, as represented by block 550. This may include outputting thehybrid output both audibly and visually in some instances. The processis then repeated again for new sensor data at time, t(2), as representedby the arrow drawn from block 545 to block 505.

However, if it is determined at block 530 that the hybrid output istransitioning from uncompensated analyte levels to lag-compensatedanalyte levels (e.g., the hybrid output was tracking an uncompensatedanalyte level, or is at a transitional value during the transitionprocess from uncompensated analyte levels to lag-compensated analytelevels), then a smoothing function is implemented (or continued to beimplemented), as represented by block 535.

At block 535, a weighted combination of the uncompensated analyte level(calculated at block 510) and the lag-compensated analyte level(generated at block 525) is used as the hybrid output. The weightedcombination may vary over the transition period—e.g., such that theweighting of the lag-compensated analyte level and the uncompensatedanalyte level vary throughout the duration of the transition period. Thehybrid output may then be output audibly or visually via a speaker ordisplay, as represented by block 540. The process is then repeated againfor new sensor data at time, t(2), as represented by the arrow drawnfrom block 540 to block 505.

Referring back to block 520, if the selected analyte level (i.e., mostrecently generated lag-compensated analyte level) has been rising for apredetermined duration of time, then the criteria for trackinguncompensated analyte levels is met and the hybrid output is determinedto track the uncompensated analyte levels. At block 555, it isdetermined whether the hybrid output is transitioning fromlag-compensated analyte levels to uncompensated analyte levels. If it isdetermined that the hybrid output is not transitioning, then the hybridanalyte level output tracks the uncompensated analyte level, asrepresented by block 570. For example, if the hybrid output was trackingan uncompensated analyte level at time, t(0), then it will be determinedthat the hybrid output is not transitioning from lag-compensated analytelevels to uncompensated analyte levels. The hybrid output is then outputaudibly or visually for the user—e.g., via a speaker or display on theanalyte monitoring device, as represented by block 575.This may includeoutputting the hybrid output both audibly and visually in someinstances. The process is then repeated again for new sensor data attime, t(2), as represented by the arrow drawn from block 570 to block505.

However, if it is determined at block 555 that the hybrid output istransitioning from lag-compensated analyte levels to uncompensatedanalyte levels (e.g., the hybrid output at time, t(0), was tracking alag-compensated analyte level, or was at a transitional value during thetransition process from lag-compensated analyte levels to uncompensatedanalyte levels), then a smoothing function is implemented (or continuedto be implemented), as represented by block 560.

At block 560, a weighted combination of the uncompensated analyte level(calculated at block 510) and the lag-compensated analyte level is usedas the hybrid output. A lag-compensated filter is applied to theuncompensated analyte level at block 560 to generate the lag-compensatedanalyte level. In another embodiment, the lag-compensated analyte levelgenerated at block 525 of time, t(0), is used. The weighted combinationmay vary over the transition period—e.g., such that the weighting of thelag-compensated analyte level and the uncompensated analyte level varythroughout the duration of the transition period. The hybrid output maythen be output audibly or visually via a speaker or display, asrepresented by block 565. The process is then repeated again for newsensor data at time, t(2), as represented by the arrow drawn from block565 to block 505.

In another embodiment, the lag-compensation filter is applied to theuncompensated analyte level after block 510 and before the comparison tothe predetermined criteria. A lag-compensated analyte level is thusgenerated for each cycle whether or not the hybrid output is determinedto track uncompensated analyte levels or lag-compensated analyte levels.In such case, the lag-compensated analyte level generated may be usedwhen the hybrid output tracks the lag-compensated analyte level (e.g.,block 545) and when the weighted combinations are generated (e.g.,blocks 535 and 560).

As similarly described above for FIG. 4, in some aspects, another signalmay be presented on the user interface instead of the hybrid outputsignal, or in addition to the hybrid output signal. For example, incertain embodiments, the lag-compensated analyte levels are provided onthe user interface instead of the hybrid output, and the hybrid outputis used to drive a “low analyte level” (e.g., low glucose level)indicator on the user interface according to predetermined criteria. Forthe sake of brevity and clarity, the above discussion in FIG. 4 is notrepeated here, but should be understood to be similarly applicable.

FIGS. 6-13 illustrate example transitions between lag-compensatedanalyte levels and uncompensated analyte levels. Only a portion of thegraph associated with the described transition is shown in the figures,as denoted by the curved line breaks on each side of the analyte levels.

FIG. 6A illustrates a chart of a hybrid output as it transitions fromlag-compensated analyte levels to uncompensated analyte levels,according to one embodiment. For the exemplary embodiment shown, thepredetermined criteria includes criteria for continuing to track thelag-compensated analyte levels until the selected analyte level is belowthe threshold value T and rising for a predetermined duration of time.

In the embodiment shown, the graph begins with the hybrid outputtracking the lag-compensated analyte level, and the most recentlycalculated lag-compensated is used as the selected analyte level forcomparison to the predetermined criteria. The lag-compensated analytelevel (and thus selected analyte level) is above the predeterminedthreshold. Thus, the criteria for tracking the lag-compensated analytelevel is still met.

Thus, as shown, where the lag-compensated analyte level crosses belowthe threshold line T, the selected analyte level drops below thethreshold line T but has not been rising for a predetermined duration oftime. Thus, the criteria for tracking the lag-compensated analyte levelis still met.

At point A (time=t_(A)), the lag-compensated analyte level (and thusselected analyte level) is below the threshold value and begins to rise.However, the lag-compensated analyte levels have not been rising for apredetermined duration of time (e.g., Δt). Thus, the criteria fortracking the lag-compensated analyte level is still met.

At point B (time=t_(B)), the lag-compensated analyte level (and thusselected analyte level) has been rising for the predetermined durationof time (e.g., Δt) and is also below the threshold value T. Thus, theselected analyte level now meets the predetermined criteria for thehybrid output to track the uncompensated analyte level. As shown in thegraph, the hybrid output tracks the uncompensated analyte levels at timet_(B). In the embodiment shown, no smoothing function is implemented andthus the hybrid output jumps from the lag-compensated analyte levels tothe uncompensated analyte levels.

After the hybrid output begins tracking the uncompensated analytelevels, a selected analyte level is compared to the predeterminedcriteria to determine when to stop tracking the uncompensated analytelevels and to start tracking the lag-compensated analyte levels again.The selected analyte level may or may not be derived from the samesource after the transition. For example, in one embodiment, the mostrecently generated lag-compensated analyte level continues to be used asthe selected analyte level that is compared to the predeterminedcriteria. In another embodiment, for example, the most recentlycalculated uncompensated analyte level may now be used as the selectedanalyte level that is compared to the predetermined criteria.

FIG. 6B illustrates a chart of a hybrid output as it transitions fromlag-compensated analyte levels to uncompensated analyte levels,according to one embodiment. The example embodiment shown in FIG. 6Bdiffers from the example embodiment shown in FIG. 6A by having asmoothing function implemented for the transition. For the sake ofbrevity and clarity, only the transition period is discussed for FIG.6B.

As similarly described above for FIG. 6A, at point B, thelag-compensated analyte level (and thus selected analyte level) is belowthe threshold value and has been rising for the predetermined durationof time (e.g., At). Thus, the criteria is now met for the hybrid outputto stop tracking the lag-compensated analyte levels and to starttracking the uncompensated analyte levels. Since the hybrid output istransitioning, a smoothing function is applied to provide a smoothtransition from the lag-compensated analyte levels to uncompensatedanalyte levels. For example, the smoothing function may include weightedcombinations of lag-compensated and uncompensated analyte levels thatvary over the transition period. At point P, the hybrid output hascompletely transitioned to the uncompensated analyte levels and thesmoothing function is no longer applied.

FIG. 7A illustrates a chart of a hybrid output as it transitions fromlag-compensated analyte levels to uncompensated analyte levels,according to one embodiment. For the exemplary embodiment shown, thepredetermined criteria includes criteria for continuing to track thelag-compensated analyte levels until the selected analyte level is belowthe threshold value T and rising for a predetermined duration of time.

In the embodiment of FIG. 7A, the graph begins with the hybrid outputtracking the lag-compensated analyte level, and the most recentlycalculated uncompensated analyte level is used as the selected analytelevel for comparison to the predetermined criteria. The uncompensatedanalyte level (and thus selected analyte level) is above thepredetermined threshold. Thus, the criteria for tracking thelag-compensated analyte level is still met.

Thus, as shown, where the uncompensated analyte level crosses below thethreshold line T, the selected analyte level drops below the thresholdline T but has not been rising for a predetermined duration of time.Thus, the criteria for tracking the lag-compensated analyte level isstill met.

At point C (time=t_(c)), the uncompensated analyte level (and thusselected analyte level) is below the threshold value and begins to rise.However, the uncompensated analyte levels have not been rising for apredetermined duration of time (e.g., Δt). Thus, the criteria fortracking the lag-compensated analyte levels is still met.

At point D (time=t_(D)), the uncompensated analyte level (and thusselected analyte level) has been rising for the predetermined durationof time (e.g., Δt) and is also below the threshold value T. Thus, theselected analyte level now meets the predetermined criteria for thehybrid output to track the uncompensated analyte level. As shown in thegraph, the hybrid output tracks the uncompensated analyte level at pointD. In the embodiment shown, no smoothing function is implemented andthus the hybrid output jumps from the lag-compensated analyte levels tothe uncompensated analyte levels.

After the hybrid output begins tracking the lag-compensated analytelevels, a selected analyte level is compared to the predeterminedcriteria to determine when to stop tracking the uncompensated analytelevels and to start tracking the lag-compensated analyte levels again.The selected analyte level may or may not be derived from the samesource after the transition. For example, in one embodiment, the mostrecently calculated uncompensated analyte level continues to be used asthe selected analyte level that is compared to the predeterminedcriteria. In another embodiment, for example, the most recentlygenerated lag-compensated analyte level, or the most recently generatedhybrid output, may now be used as the selected analyte level that iscompared to the predetermined criteria.

FIG. 7B illustrates a chart of a hybrid output as it transitions fromlag-compensated analyte levels to uncompensated analyte levels,according to one embodiment. The example embodiment shown in FIG. 7Bdiffers from the example embodiment shown in FIG. 7A by having asmoothing function implemented for the transition. For the sake ofbrevity and clarity, only the transition period is discussed for FIG.7B.

As similarly described above for FIG. 7A, at point D, the uncompensatedanalyte level (and thus selected analyte level) is below the thresholdvalue and has been rising for the predetermined duration of time (e.g.,Δt). Thus, the criteria is now met for the hybrid output to stoptracking the lag-compensated analyte levels and to start tracking theuncompensated analyte levels. Since the hybrid output is transitioning,a smoothing function is applied to provide a smooth transition from thelag-compensated analyte levels to uncompensated analyte levels. Forexample, the smoothing function may include weighted combinations oflag-compensated and uncompensated analyte levels that vary over thetransition period. At point P, the hybrid output has completelytransitioned to the uncompensated analyte levels and the smoothingfunction is no longer applied.

FIG. 8A illustrates a chart of a hybrid output as it transitions fromuncompensated analyte levels to lag-compensated analyte levels,according to one embodiment. For the exemplary embodiment shown, thepredetermined criteria includes criteria for continuing to track theuncompensated analyte levels until the selected analyte level is eithernot below the threshold value T or has not rising for a predeterminedduration of time. In another embodiment, the criteria for having notbeen rising for a predetermined duration of time may instead be“beginning to decline for a predetermined duration of time”.

In the embodiment shown, the graph begins with the hybrid outputtracking the uncompensated analyte level, and the most recentlycalculated uncompensated analyte level is used as the selected analytelevel for comparison to the predetermined criteria. The uncompensatedanalyte level (and thus selected analyte level) is shown at the start ofthe graph as being below the predetermined threshold. Furthermore, theuncompensated analyte level (and thus selected analyte level) istrending upward. Thus, the criteria for tracking the uncompensatedanalyte level is still met. If for example, the uncompensated analytelevel was below the threshold value but began to trend downward (notshown in FIG. 8A), then the criteria would not be met for tracking theuncompensated analyte level and the hybrid output would begin trackingthe lag-compensated analyte level.

At point E, the uncompensated analyte level (and thus selected analytelevel) is no longer below the threshold line T, and thus the criteriafor tracking the uncompensated analyte level is no longer met. As shownin the graph, the hybrid output begins tracking the lag-compensatedanalyte levels at time t_(E). In the embodiment shown, no smoothingfunction is implemented and thus the hybrid output jumps from theuncompensated analyte levels to the lag-compensated analyte levels.

After the hybrid output tracks the lag-compensated analyte levels, aselected analyte level is compared to the predetermined criteria todetermine when to stop tracking the lag-compensated analyte levels andto start tracking the uncompensated analyte levels again. The selectedanalyte level may or may not be derived from the same source after thetransition. For example, in one embodiment, the most recently calculateduncompensated analyte level continues to be used as the selected analytelevel that is compared to the predetermined criteria. In anotherembodiment, for example, the most recently generated lag-compensatedanalyte level (or the most recently generated hybrid output) is thenused as the selected analyte level that is compared to the predeterminedcriteria.

FIG. 8B illustrates a chart of a hybrid output as it transitions fromuncompensated analyte levels to lag-compensated analyte levels,according to one embodiment. The example embodiment shown in FIG. 8Bdiffers from the example embodiment shown in FIG. 8A by having asmoothing function implemented for the transition. For the sake ofbrevity and clarity, only the transition period is discussed for FIG.8B.

As similarly described above for FIG. 8A, at point E, the uncompensatedanalyte level (and thus selected analyte level) is no longer below thethreshold value. Thus, the criteria is now met for the hybrid output tostop tracking the uncompensated analyte levels and to start tracking thelag-compensated analyte levels. Since the hybrid output istransitioning, a smoothing function is applied to provide a smoothtransition from the uncompensated analyte levels to lag-compensatedanalyte levels. For example, the smoothing function may include weightedcombinations of lag-compensated and uncompensated analyte levels thatvary over the transition period. At point P, the hybrid output hascompletely transitioned to the lag-compensated analyte levels and thesmoothing function is no longer applied.

FIG. 9A illustrates a chart of a hybrid output as it transitions fromuncompensated analyte levels to lag-compensated analyte levels,according to one embodiment. For the exemplary embodiment shown, thepredetermined criteria includes criteria for continuing to track theuncompensated analyte levels until the selected analyte level is eithernot below the threshold value T or has not rising for a predeterminedduration of time.

In the embodiment shown, the graph begins with the hybrid outputtracking the uncompensated analyte level, and the most recentlycalculated lag-compensated analyte level is used as the selected analytelevel for comparison to the predetermined criteria. The lag-compensatedanalyte level (and thus selected analyte level) is shown at the start ofthe graph to be below the predetermined threshold. Furthermore, thelag-compensated analyte level (and thus selected analyte level) istrending upward. Thus, the criteria for tracking the uncompensatedanalyte level is still met. If, for example, the lag-compensated analytelevel was below the threshold value but began to trend downward (notshown in FIG. 9A), then the criteria would not be met for tracking theuncompensated analyte level and the hybrid output would begin trackingthe lag-compensated analyte level.

At point F, the lag-compensated analyte level (and thus selected analytelevel) is no longer below the threshold line T, and thus the criteriafor tracking the uncompensated analyte level is no longer met. As shownin the graph, the hybrid output begins tracking the lag-compensatedanalyte levels at time t_(F). In the embodiment shown, no smoothingfunction is implemented and thus the hybrid output jumps from theuncompensated analyte levels to the lag-compensated analyte levels.

After the hybrid output begins tracking the lag-compensated analytelevels, a selected analyte level is compared to the predeterminedcriteria to determine when to stop tracking the lag-compensated analytelevels and to start tracking the uncompensated analyte levels again. Theselected analyte level may or may not be derived from the same sourceafter the transition. For example, in one embodiment, the most recentlygenerated lag-compensated analyte level continues to be used as theselected analyte level that is compared to the predetermined criteria.In another embodiment, for example, the most recently calculateduncompensated analyte level (or the most recently generated hybridoutput) is now used as the selected analyte level that is compared tothe predetermined criteria.

FIG. 9B illustrates a chart of a hybrid output as it transitions fromuncompensated analyte levels to lag-compensated analyte levels,according to one embodiment. The example embodiment shown in FIG. 9Bdiffers from the example embodiment shown in FIG. 9A by having asmoothing function implemented for the transition. For the sake ofbrevity and clarity, only the transition period is discussed for FIG.9B.

As similarly described above for FIG. 9A, at point F, thelag-compensated analyte level (and thus selected analyte level) is nolonger below the threshold value T. Thus, the criteria is now met forthe hybrid output to stop tracking the uncompensated analyte levels andto start tracking the lag-compensated analyte levels. Since the hybridoutput is transitioning, a smoothing function is applied to provide asmooth transition from the uncompensated analyte levels tolag-compensated analyte levels. For example, the smoothing function mayinclude weighted combinations of lag-compensated and uncompensatedanalyte levels that vary over the transition period. At point P, thehybrid output has completely transitioned to the lag-compensated analytelevels and the smoothing function is no longer applied.

FIG. 10 illustrates a flowchart for a method of generating a hybridanalyte level output, according to one embodiment. In some instances,such as with CGM systems and intermittent or periodic interrogationanalyte sensing systems, sensor data continues to be received over time.

In the embodiment illustrated in FIG. 10, the analyte (or sensor) dataare received periodically at 1000. This sensor data may be “raw”,meaning that it would need to be processed to represent the analytelevel. For instance, the raw sensor data may need to be multiplied by aconversion factor to represent an analyte level. Furthermore, an analytelevel may be determined, sometimes in the form of a filter, from themost recently received sensor data in conjunction with one or morehistorical sensor data retrieved from memory. These and other forms ofprocessing raw sensor data to determine an analyte level are well knownin the art.

Two analyte levels (e.g., glucose levels) are determined by processingthe raw data, as illustrated in FIG. 10. At 1010, uncompensated analytelevels, termed as _(GISF,) are determined for each sensor data receivedwhich represent, for instance, ISF glucose levels. At 1020, compensatedanalyte levels, termed as G_(BG), are determined for each sensor datareceived which represent, for instance, blood glucose (BG) levels. TheBG levels may be distinct from the ISF levels, in that the BG levelshave been corrected for lag, using lag correction techniques that arewell known in the art.

The hybrid output analyte level output, G_(HYB), is determined by thepredetermined criteria in process in 1030. This process is executed forevery received sensor data. Inputs to the process are the compensatedand uncompensated levels, predetermined parameters retrieved from memory(1040), for example, in this embodiment, a threshold parameter, G_(LOW),and a transition-smoothing time-constant parameter, τ. The process alsohas inputs in the form of feedback from the output of the process at itsprior executions; these variables, X_(STATE) and t_(DECAY), along withτ, are used to manage the transition smoothing. For this embodiment,there are three possible values for X_(STATE); “use G_(BG)”,“useminimum” or “use transition”. τ is a constant, such as 10; for sensorreceived every minute, τ would equal 10 minutes. The variable t_(DECAY)will vary from 0 to τ, as incremented by the process 1030. Finally, thehybrid signal itself is a state variable fed back into the process 1030.

The description of the process 1030 can be described by pseudo-codegiven below. The initial state is set to G_(HYB)=G_(BG), X_(STATE)=“useG_(BG)” and t_(DECAY)=0. The hybrid output will be determined accordingto the predetermined criteria based on the two level inputs as describedin the logic below:

If (G_(HYB)(−)>G_(LOW)) AND (x_(STATE)(−)=“useG_(GB)”), thenG_(HYB)=G_(BG), X_(STATE)=“use G_(BG)”, and t_(DECAY)=0;

If (G_(HYB)(−)<=G_(LOW)), then G_(HYB)=minimum(G_(BG), G_(ISF)),X_(STATE)=“use minimum”, and t_(DECAY)=0;

If (G_(HYB)(−)>G_(LOW)) AND (x_(STATE)(−)=“use minimum”), thenG_(HYB)=minimum(G_(BG), G_(ISF)), X_(STATE)=“use transition”, andt_(DECAY)=1;

If (G_(HYB)(−)>G_(LOW)) AND (x_(STATE)(−)=“use transition”) AND(t_(DECAY)(−)<τ), then G_(HYB)=((τ−t_(DECAY))/τ)*minimum(G_(BG),G_(ISF))+(t_(DECAY)/τ)*G_(BG), x_(STATE)=“use transition”, andt_(DECAY)=t_(DECAY)(−)+1;

If (G_(HYB)(−)>G_(LOW)) AND (x_(STATE)(−)=“use transition”) AND(t_(DECAY)(−)=τ), then G_(HYB)=G_(BG), x_(STATE)=“use G_(BG)”, andt_(DECAY)=0;

where the symbol “(−)” denotes a state variable value from the previousprocess execution, and variables without this symbol are assumed to befor the present execution.

The logic describe above provides a process where the hybrid levelreflects the blood glucose level until it transitions below the lowglucose threshold, where it reflects the lower of the blood glucose orISF glucose level. When the hybrid output rises above the low glucosethreshold, the last three logical statements provide a state machinethat smoothly transitions the hybrid signal from this minimum level tothe blood glucose level. This function will behave similarly asillustrated in FIG. 3. In addition, when the hybrid level falls belowthe low glucose threshold before a transition has completed (that is,when 0<(t_(DECAY)(−)<τ), the behavior of this logic is acceptable inthat the hybrid output would return to the lower of the two inputlevels, as directed by the second logic statement.

The hybrid output, _(GHYB,) may be used the same as any analyte level iscommonly used in a system. For instance, glucose levels determined by aCGM system are commonly used in display to the patient or care giver, inlogging in memory for future upload and analysis, and in monitoring byalarm monitoring functions. The hybrid output would be used in the sameway. As mentioned, one advantage of the hybrid output is in its use foralarm monitoring and display, such that the BG level provides promptwarning of low blood glucose levels to the patient, while the ISFglucose level provides a conservative measure of lingering low ISFglucose while the blood glucose is rising.

Variations of this embodiment should be readily apparent. For instance,the processes may be run at frequencies different from the frequency ofreceived sensor data, such as every other received data or every fifthreceived data. Also, this invention may be generalized to combine morethan two levels according to a predetermined criterion. In addition,this invention may be generalized to include two or more constantthresholds as parameters in the predetermined criterion for determininga hybrid level; for instance, one threshold may be used for switchingthe hybrid level to the minimum of the BG or ISF levels, and anotherthreshold may be used for switching the hybrid level back totransitioning to the BG level. In addition, the predetermined parametersmay have different values that may be set by the operator or set by someother condition automatically detected by this system or another system.Also, the predetermined criterion for generating the hybrid level mayincorporate more complicated or advanced forms of filtering or smoothingthan what is described here.

Devices and Systems

Embodiments of the present disclosure relate to methods, devices, andsystems for detecting at least one analyte, including glucose, in bodyfluid. Embodiments relate to the continuous, periodic, and intermitted)in vivo monitoring of the level of one or more analytes using acontinuous or on-demand analyte monitoring device or system. The systemmay include an analyte sensor at least a portion of which is to bepositioned beneath a skin surface of a user for a period of time. Thepresent disclosure may also be applicable to discrete monitoring of oneor more analytes using an in vitro blood glucose (“BG”) meter and ananalyte test strip.

Embodiments include combined or combinable devices, systems and methodsand/or transferring data between an in vivo continuous system and an invivo system. In one embodiment, the systems, or at least a portion ofthe systems, are integrated into a single unit.

For example, the analyte monitoring devices and systems may include, orcommunicate with, an analyte sensor at least a portion of which ispositionable beneath the skin surface of the user for the in vivodetection of an analyte, including glucose, lactate, and the like, in abody fluid. Embodiments include wholly implantable analyte sensors andanalyte sensors in which only a portion of the sensor is positionedunder the skin and a portion of the sensor resides above the skin, e.g.,for contact to a sensor control unit (which may include a communicationmodule, e.g., a transmitter or the like), a receiver/display unit,transceiver, processor, etc. The sensor may be, for example,subcutaneously positionable in a user for the continuous, periodic, oron-demand monitoring of a level of an analyte in the user's interstitialfluid.

In one embodiment, an analyte sensor may be positioned in contact withinterstitial fluid to detect the level of glucose, which detectedglucose may be used to infer the glucose level in the user'sbloodstream. Embodiments of the analyte sensors may be configured formonitoring the level of the analyte over a time period which may rangefrom seconds, minutes, hours, days, weeks, to months, or longer.

In one embodiment, the analyte sensors, such as glucose sensors, arecapable of in vivo detection of an analyte for one hour or more, e.g., afew hours or more, e.g., a few days or more, e.g., three or more days,e.g., five days or more, e.g., seven days or more, e.g., several weeksor more, or one month or more.

As demonstrated herein, the methods of the present disclosure are usefulin connection with a device that is used to measure or monitor ananalyte (e.g., glucose), such as any such device described herein. Thesemethods may also be used in connection with a device that is used tomeasure or monitor another analyte (e.g., ketones, ketone bodies, HbAlc,and the like), including oxygen, carbon dioxide, proteins, drugs, oranother moiety of interest, for example, or any combination thereof,found in bodily fluid, including subcutaneous fluid, dermal fluid(sweat, tears, and the like), interstitial fluid, or other bodily fluidof interest, for example, or any combination thereof.

FIG. 11 shows an analyte (e.g., glucose) monitoring system, according toone embodiment. Aspects of the subject disclosure are further describedprimarily with respect to glucose monitoring devices and systems, andmethods of glucose detection, for convenience only and such descriptionis in no way intended to limit the scope of the embodiments. It is to beunderstood that the analyte monitoring system may be configured tomonitor a variety of analytes at the same time or at different times.

Analytes that may be monitored include, but are not limited to, acetylcholine, amylase, bilirubin, cholesterol, chorionic gonadotropin,glycosylated hemoglobin (HbAlc), creatine kinase (e.g., CK-MB),creatine, creatinine, DNA, fructosamine, glucose, glucose derivatives,glutamine, growth hormones, hormones, ketones, ketone bodies, lactate,peroxide, prostate-specific antigen, prothrombin, RNA, thyroidstimulating hormone, and troponin. The concentration of drugs, such as,for example, antibiotics (e.g., gentamicin, vancomycin, and the like),digitoxin, digoxin, drugs of abuse, theophylline, and warfarin, may alsobe monitored. In embodiments that monitor more than one analyte, theanalytes may be monitored at the same or different times.

The analyte monitoring system 1400 includes an analyte sensor 1401, adata processing unit 1402 connectable to the sensor 1401, and a primaryreceiver unit 1404. In some instances, the primary receiver unit 1404 isconfigured to communicate with the data processing unit 1402 via acommunication link 1403. In one embodiment, the primary receiver unit1404 may be further configured to transmit data to a data processingterminal 1405 to evaluate or otherwise process or format data receivedby the primary receiver unit 1404. The data processing terminal 1405 maybe configured to receive data directly from the data processing unit1402 via a communication link 1407, which may optionally be configuredfor bi-directional communication. Further, the data processing unit 1402may include a transmitter or a transceiver to transmit and/or receivedata to and/or from the primary receiver unit 1404 and/or the dataprocessing terminal 1405 and/or optionally a secondary receiver unit1406.

Also shown in FIG. 11 is an optional secondary receiver unit 1406 whichis operatively coupled to the communication link 1403 and configured toreceive data transmitted from the data processing unit 1402. Thesecondary receiver unit 1406 may be configured to communicate with theprimary receiver unit 1404, as well as the data processing terminal1405. In one embodiment, the secondary receiver unit 1406 may beconfigured for bi-directional wireless communication with each of theprimary receiver unit 1404 and the data processing terminal 1405. Asdiscussed in further detail below, in some instances, the secondaryreceiver unit 1406 may be a de-featured receiver as compared to theprimary receiver unit 1404, for instance, the secondary receiver unit1406 may include a limited or minimal number of functions and featuresas compared with the primary receiver unit 1404. As such, the secondaryreceiver unit 1406 may include a smaller (in one or more, including all,dimensions), compact housing or embodied in a device including a wristwatch, arm band, PDA, mp3 player, cell phone, etc., for example.Alternatively, the secondary receiver unit 106 may be configured withthe same or substantially similar functions and features as the primaryreceiver unit 1404. The secondary receiver unit 106 may include adocking portion configured to mate with a docking cradle unit forplacement by, e.g., the bedside for night time monitoring, and/or abi-directional communication device. A docking cradle may recharge apower supply.

Only one analyte sensor 1401, data processing unit 1402 and dataprocessing terminal 1405 are shown in the embodiment of the analytemonitoring system 1400 illustrated in FIG. 11. However, the analytemonitoring system 1400 may include more than one sensor 1401 and/or morethan one data processing unit 1402, and/or more than one data processingterminal 1405. Multiple sensors may be positioned in a user for analytemonitoring at the same or different times.

The analyte monitoring system 1400 may be a continuous monitoringsystem, or semi-continuous, or a discrete monitoring system. In amulti-component environment, each component may be configured to beuniquely identified by one or more of the other components in the systemso that communication conflict may be readily resolved between thevarious components within the analyte monitoring system 1400. Forexample, unique IDs, communication channels, and the like, may be used.

In one embodiment, the sensor 1401 is physically positioned in or on thebody of a user whose analyte level is being monitored. The sensor 1401may be configured to at least periodically sample the analyte level ofthe user and convert the sampled analyte level into a correspondingsignal for transmission by the data processing unit 1402. The dataprocessing unit 1402 is coupleable to the sensor 1401 so that bothdevices are positioned in or on the user's body, with at least a portionof the analyte sensor 1401 positioned transcutaneously. The dataprocessing unit may include a fixation element, such as an adhesive orthe like, to secure it to the user's body. A mount (not shown)attachable to the user and mateable with the data processing unit 1402may be used. For example, a mount may include an adhesive surface. Thedata processing unit 1402 performs data processing functions, where suchfunctions may include, but are not limited to, filtering and encoding ofdata signals, each of which corresponds to a sampled analyte level ofthe user, for transmission to the primary receiver unit 1404 via thecommunication link 1403. In one embodiment, the sensor 1401 or the dataprocessing unit 1402 or a combined sensor/data processing unit may bewholly implantable under the skin surface of the user.

In one embodiment, the primary receiver unit 1404 may include an analoginterface section including an RF receiver and an antenna that isconfigured to communicate with the data processing unit 1402 via thecommunication link 1403, and a data processing section for processingthe received data from the data processing unit 1402 including datadecoding, error detection and correction, data clock generation, databit recovery, etc., or any combination thereof.

In operation, the primary receiver unit 1404 in one embodiment isconfigured to synchronize with the data processing unit 1402 to uniquelyidentify the data processing unit 1402, based on, for example, anidentification information of the data processing unit 1402, andthereafter, to periodically receive signals transmitted from the dataprocessing unit 1402 associated with the monitored analyte levelsdetected by the sensor 1401.

Referring again to FIG. 11, the data processing terminal 1405 mayinclude a personal computer, a portable computer including a laptop or ahandheld device such as a consumer electronics device (e.g., a personaldigital assistant (PDA), a telephone including a cellular phone (e.g., amultimedia and Internet-enabled mobile phone including an iPhone™, aBlackberry®, or similar phone), an mp3 player (e.g., an iPOD™, etc.), apager, and the like), and/or a drug delivery device (e.g., an infusiondevice), each of which may be configured for data communication with thereceiver via a wired or a wireless connection. Additionally, the dataprocessing terminal 1405 may further be connected to a data network (notshown) for storing, retrieving, updating, and/or analyzing datacorresponding to the detected analyte level of the user.

The data processing terminal 1405 may include a drug delivery device(e.g., an infusion device) such as an insulin infusion pump or the like,which may be configured to administer a drug (e.g., insulin) to theuser, and which may be configured to communicate with the primaryreceiver unit 104 for receiving, among others, the measured analytelevel. Alternatively, the primary receiver unit 1404 may be configuredto integrate an infusion device therein so that the primary receiverunit 1404 is configured to administer an appropriate drug (e.g.,insulin) to users, for example, for administering and modifying basalprofiles, as well as for determining appropriate boluses foradministration based on, among others, the detected analyte levelsreceived from the data processing unit 1402. An infusion device may bean external device or an internal device, such as a device whollyimplantable in a user.

In one embodiment, the data processing terminal 1405, which may includean infusion device, e.g., an insulin pump, may be configured to receivethe analyte signals from the data processing unit 1402, and thus,incorporate the functions of the primary receiver unit 1404 includingdata processing for managing the user's insulin therapy and analytemonitoring. In one embodiment, the communication link 1403, as well asone or more of the other communication interfaces shown in FIG. 11, mayuse one or more wireless communication protocols, such as, but notlimited to: an RF communication protocol, an infrared communicationprotocol, a Bluetooth enabled communication protocol, an 802.11xwireless communication protocol, or an equivalent wireless communicationprotocol which would allow secure, wireless communication of severalunits (for example, per Health Insurance Portability and AccountabilityAct (HIPPA) requirements), while avoiding potential data collision andinterference.

FIG. 12 is a block diagram of the data processing unit 1402 shown inFIG. 11 in accordance with one embodiment. Data processing unit 1402includes an analog interface 1501 configured to communicate with thesensor 1401 (FIG. 1), a user input 1502 , and a temperature measurementsection 1503, each of which is operatively coupled to processor 1504such as a central processing unit (CPU). Furthermore, unit 1402 is shownto include a serial communication section 1505, clock 1508, and an RFtransmitter 1506, each of which is also operatively coupled to theprocessor 1504. Moreover, a power supply 1507 such as a battery is alsoprovided in unit 1402 to provide the necessary power.

In another embodiment, the data processing unit may not include allcomponents in the exemplary embodiment shown. User input and/orinterface components may be included or a data processing unit may befree of user input and/or interface components. In one embodiment, oneor more application-specific integrated circuits (ASIC) may be used toimplement one or more functions or routines associated with theoperations of the data processing unit (and/or receiver unit) using forexample one or more state machines and buffers.

As can be seen in the embodiment of FIG. 12, the analyte sensor 1401(FIG. 1) includes four contacts, three of which are electrodes: a workelectrode (W) 1510, a reference electrode (R) 1512, and a counterelectrode (C) 1513, each operatively coupled to the analog interface1501 of the data processing unit 1402. This embodiment also shows anoptional guard contact (G) 1511. Fewer or greater electrodes may beemployed. For example, the counter and reference electrode functions maybe served by a single counter/reference electrode. In some cases, theremay be more than one working electrode and/or reference electrode and/orcounter electrode, etc.

FIG. 13 is a block diagram of an embodiment of a receiver/monitor unitsuch as the primary receiver unit 1404 of the analyte monitoring systemshown in FIG. 11. The primary receiver unit 1404 includes one or moreof: a test strip interface 1601, an RF receiver 1602, a user input 1603,an optional temperature detection section 1604, and a clock 1605, eachof which is operatively coupled to a processing and storage section1607. The primary receiver unit 1404 also includes a power supply 1606operatively coupled to a power conversion and monitoring section 1608.Further, the power conversion and monitoring section 1608 is alsocoupled to the processing and storage section 1607. Moreover, also shownare a receiver serial communication section 1609, and an output 1610,each operatively coupled to the processing and storage section 1607. Theprimary receiver unit 1404 may include user input and/or interfacecomponents or may be free of user input and/or interface components.

In one embodiment, the test strip interface 1601 includes an analytetesting portion (e.g., a glucose level testing portion) to receive ablood (or other body fluid sample) analyte test or information relatedthereto. For example, the test strip interface 1601 may include a teststrip port to receive a test strip (e.g., a glucose test strip). Thedevice may determine the analyte level of the test strip, and optionallydisplay (or otherwise notice) the analyte level on the output 1610 ofthe primary receiver unit 1404. Any suitable test strip may be employed,e.g., test strips that only require a very small amount (e.g., 3microliters or less, e.g., 1 microliter or less, e.g., 0.5 microlitersor less, e.g., 0.1 microliters or less), of applied sample to the stripin order to obtain accurate glucose information. Embodiments of teststrips include, e.g., Freestyle® and Precision® blood glucose teststrips from Abbott Diabetes Care, Inc. (Alameda, Calif.). Glucoseinformation obtained by an in vitro glucose testing device may be usedfor a variety of purposes, computations, etc. For example, theinformation may be used to calibrate sensor 1401, confirm results ofsensor 1401 to increase the confidence thereof (e.g., in instances inwhich information obtained by sensor 1401 is employed in therapy relateddecisions), etc.

In further embodiments, the data processing unit 1402 and/or the primaryreceiver unit 1404 and/or the secondary receiver unit 1406, and/or thedata processing terminal/infusion device 1405 may be configured toreceive the analyte value wirelessly over a communication link from, forexample, a blood glucose meter. In further embodiments, a usermanipulating or using the analyte monitoring system 1400 (FIG. 11) maymanually input the analyte value using, for example, a user interface(for example, a keyboard, keypad, voice commands, and the like)incorporated in one or more of the data processing unit 1402, theprimary receiver unit 1404, secondary receiver unit 1406, or the dataprocessing terminal/infusion device 1405.

The features and techniques described in the present disclosure may beperformed, for example, by the processing circuitry within the dataprocessing unit 1402 or receiving unit 1404, or combination of both.

Additional detailed descriptions are provided in U.S. Pat. Nos.5,262,035; 5,264,104; 5,262,305; 5,320,715; 5,593,852; 6,175,752;6,650,471; 6,746, 582, and 7,811,231, each of which is incorporatedherein by reference in their entirety.

In one embodiment of the present disclosure, the analyte monitoringdevice includes processing circuitry that is able to determine a levelof the analyte and activate an alarm system if the analyte level exceedsa threshold. The analyte monitoring device, in these embodiments, has analarm system and may also include a display, such as an LCD or LEDdisplay.

A threshold value is exceeded if the datapoint has a value that isbeyond the threshold value in a direction indicating a particularcondition. For example, a datapoint which correlates to a glucose levelof 200 mg/dL exceeds a threshold value for hyperglycemia of 180 mg/dL,because the datapoint indicates that the user has entered ahyperglycemic state. As another example, a datapoint which correlates toa glucose level of 65 mg/dL exceeds a threshold value for hypoglycemiaof 70 mg/dL because the datapoint indicates that the user ishypoglycemic as defined by the threshold value. However, a datapointwhich correlates to a glucose level of 75 mg/dL would not exceed thesame threshold value for hypoglycemia because the datapoint does notindicate that particular condition as defined by the chosen thresholdvalue.

An alarm may also be activated if the sensor readings indicate a valuethat is beyond a measurement range of the sensor. For glucose, thephysiologically relevant measurement range may be 30-400 mg/dL,including 40-300 mg/dL and 50-250 mg/dL, of glucose in the interstitialfluid.

The alarm system may also, or alternatively, be activated when the rateof change or acceleration of the rate of change in analyte levelincrease or decrease reaches or exceeds a threshold rate oracceleration. For example, in the case of a subcutaneous glucosemonitor, the alarm system might be activated if the rate of change inglucose concentration exceeds a threshold value which might indicatethat a hyperglycemic or hypoglycemic condition is likely to occur.

A system may also include system alarms that notify a user of systeminformation such as battery condition, calibration, sensor dislodgment,sensor malfunction, etc. Alarms may be, for example, auditory and/orvisual. Other sensory-stimulating alarm systems may be used includingalarm systems which heat, cool, vibrate, or produce a mild electricalshock when activated.

Drug Delivery System

The present disclosure also includes sensors used in sensor-based drugdelivery systems. The system may provide a drug to counteract the highor low level of the analyte in response to the signals from one or moresensors. Alternatively, the system may monitor the drug concentration toensure that the drug remains within a desired therapeutic range. Thedrug delivery system may include one or more (e.g., two or more)sensors, a processing unit such as a transmitter, a receiver/displayunit, and a drug administration system. In some cases, some or allcomponents may be integrated in a single unit. A sensor-based drugdelivery system may use data from the one or more sensors to providenecessary input for a control algorithm/mechanism to adjust theadministration of drugs, e.g., automatically or semi-automatically. Asan example, a glucose sensor may be used to control and adjust theadministration of insulin from an external or implanted insulin pump.

Each of the various references, presentations, publications, provisionaland/or non-provisional U.S. Patent Applications, U.S. Patents, non-U.S.Patent Applications, and/or non-U.S. Patents that have been identifiedherein, is incorporated herein by reference in its entirety.

Other embodiments and modifications within the scope of the presentdisclosure will be apparent to those skilled in the relevant art.Various modifications, processes, as well as numerous structures towhich the embodiments of the present disclosure may be applicable willbe readily apparent to those of skill in the art to which the presentdisclosure is directed upon review of the specification. Various aspectsand features of the present disclosure may have been explained ordescribed in relation to understandings, beliefs, theories, underlyingassumptions, and/or working or prophetic examples, although it will beunderstood that the present disclosure is not bound to any particularunderstanding, belief, theory, underlying assumption, and/or working orprophetic example. Although various aspects and features of the presentdisclosure may have been described largely with respect to applications,or more specifically, medical applications, involving diabetic humans,it will be understood that such aspects and features also relate to anyof a variety of applications involving non-diabetic humans and any andall other animals. Further, although various aspects and features of thepresent disclosure may have been described largely with respect toapplications involving partially in vivo positioned sensors, such astranscutaneous or subcutaneous sensors, it will be understood that suchaspects and features also relate to any of a variety of sensors that aresuitable for use in connection with the body of an animal or a human,such as those suitable for use as fully implanted in the body of ananimal or a human. Finally, although the various aspects and features ofthe present disclosure have been described with respect to variousembodiments and specific examples herein, all of which may be made orcarried out conventionally, it will be understood that the invention isentitled to protection within the full scope of the appended claims.

Example Embodiments

Example embodiments are provided below. The embodiments are exemplaryand not intended to be limiting. Other embodiments or variations mayalso be within the scope of the present disclosure.

In some aspects, methods of generating a hybrid analyte level output areprovided. The methods include receiving sensor data; and generating ahybrid analyte level output including uncompensated analyte levels andlag-compensated analyte levels, wherein the uncompensated analyte levelslag in time with respect to the lag-compensated analyte levels. Thehybrid analyte level output tracks between the uncompensated analytelevels and the lag-compensated analyte levels according to predeterminedcriteria.

In certain embodiments, the predetermined criteria includes criteria fortracking the uncompensated analyte levels when selected analyte levelsare below a predetermined threshold and have been rising for at least apredetermined duration of time; and criteria for tracking thelag-compensated levels when the selected analyte levels are not belowthe predetermined threshold or have not been rising for at least thepredetermined duration of time.

In certain embodiments, the predetermined criteria includes criteria forcontinuing to track the lag-compensated analyte levels until selectedanalyte levels are below a predetermined threshold and have been risingfor at least a predetermined duration of time. In certain embodiments,the predetermined criteria includes criteria for continuing to track theuncompensated analyte levels until selected analyte levels are not belowa predetermined threshold or have not been rising for at least apredetermined duration of time. In certain instances, the predeterminedthreshold related to tracking the lag-compensated analyte levels may bethe same as the predetermined threshold related to the tracking theuncompensated analyte levels in one embodiment, but different in anotherembodiment. Similarly, in certain instances, the predetermined durationof time related to tracking the lag-compensated analyte levels may bethe same as the predetermined duration of time related to the trackingthe uncompensated analyte levels in one embodiment, but different inanother embodiment.

In certain embodiments, the predetermined criteria includes criteria forcontinuing to track the uncompensated analyte levels until selectedanalyte levels are not below a first predetermined threshold or have notbeen rising for at least a first predetermined duration of time. Theselected analyte levels may vary in different embodiments. For example,in one embodiment, the selected analyte levels may include the mostrecently generated lag-compensated analyte levels. In anotherembodiment, the selected analyte levels may include the most recentlycalculated uncompensated analyte levels. In yet another embodiment, theselected analyte levels may include the most recently generated hybridanalyte level outputs. In some embodiment, the selected analyte levelsmay include one or more of the preceding sources—e.g., the most recentlygenerated lag-compensated analyte levels, the most recently calculateduncompensated analyte levels, and the most recently generated hybridanalyte level outputs. For instance, various times, conditions, events,etc., may be predetermined and associated with different sources, andwhen a time, condition, event, etc., occurs, the corresponding source isused. For example, in certain embodiments, the selected analyte levelsare selected from a first source when the hybrid analyte level outputtracks the uncompensated analyte levels, and selected from a secondsource when the hybrid analyte level output tracks the lag-compensatedanalyte levels. In certain embodiments, the selected analyte levels areselected from a first source when the hybrid analyte level output tracksthe uncompensated analyte levels, selected from a second source when thehybrid analyte level output tracks the lag-compensated analyte levels,and selected from a third source when transitioning from theuncompensated analyte levels to the lag-compensated analyte levels. Thesources are exemplary and not intended to be limiting.

The methods, devices, and systems may also include other overridingconditions, which cause the methods, devices, and systems to perform ina different manner as specific times.

The hybrid analyte level output may also include weighted combinationsof uncompensated analyte levels and the lag-compensated analyte levels.For example, in certain embodiments, the hybrid analyte level outputincludes weighted combinations of the uncompensated analyte levels andthe lag-compensated analyte levels when transitioning from theuncompensated analyte levels to the lag-compensated analyte levels. Incertain embodiments, the hybrid analyte level output includes weightedcombinations of the uncompensated analyte levels and the lag-compensatedanalyte levels when transitioning from the lag-compensated analytelevels to the uncompensated analyte levels. Weighted combinations may beused in one or both transitions in different embodiments. Furthermore,in some instances, the weighted combinations may be used for differentdurations, or at predetermined times, conditions, events, etc., indifferent embodiments.

The predetermined criteria may also include parameters that define, incertain instances, when the hybrid analyte output level tracks differentsources. For example, in certain embodiments, the predetermined criteriaincludes criteria for tracking the lag-compensated analyte level untilthe hybrid analyte output level falls below a predetermined threshold.Further, the hybrid analyte output level tracks a lower of thelag-compensated analyte level and the uncompensated analyte level whenthe hybrid analyte output level falls below the predetermined threshold.In certain embodiments, a smoothing function may be implemented duringtransitions. For example, in certain embodiment, the predeterminedcriteria includes criteria for transitioning smoothly from tracking thelower of the lag-compensated analyte level and the uncompensated analytelevel to tracking the lag-compensated analyte levels when the hybridanalyte output level rises back above the predetermined threshold.Further, this smooth transitioning may occur during a predetermined“transition-smoothing” time period. In certain embodiments, thepredetermined criteria includes criteria for tracking the lower of thelag-compensated analyte level and the uncompensated analyte level whenthe hybrid analyte output level falls back below the predeterminedthreshold before a completion of the predetermined transition-smoothingtime period.

In certain embodiments, the lag compensation may be performed on theuncompensated analyte levels—e.g., by applying a lag compensationfilter—even when the lag-compensated analyte levels are not selected foroutput. In this way, both the uncompensated analyte levels and thelag-compensated analyte levels are provided and selected between for thehybrid output. For instance, in some embodiments, both the uncompensatedanalyte levels and the lag-compensated analyte levels are generated, andthe appropriate signal presented on a user-interface. In this way, thedisplay of an analyte monitoring device, for example, displays theuncompensated analyte levels when the hybrid output tracks theuncompensated analyte levels, and displays the lag-compensated analytelevels when the hybrid output tracks the lag-compensated analyte levels.

In certain embodiments, the lag compensation filter may be applied tothe uncompensated analyte levels to generate the lag-compensated analytelevels only when the hybrid analyte level output tracks thelag-compensated levels.

In certain embodiments, the hybrid analyte level output may be presentedto the user via a user interface element on a device. For example, thehybrid analyte level output may be output audibly and/or visually with aspeaker and/or display on an analyte monitoring device. For instance,the analyte monitoring device may be a receiver that receives analytedata from an in vivo sensor. While various analytes may be applicable asdescribed above, in certain embodiments, the analyte is glucose orketone bodies. In some instances, the uncompensated analyte levels mayrepresent glucose levels derived from interstitial fluid of a patient.

In certain embodiments, the method of generating a hybrid analyte leveloutput includes calculating the uncompensated analyte levels based onthe received sensor data, wherein the sensor data is raw sensor datafrom an in vivo analyte sensor.

In some aspects, analyte monitoring devices are provided that generatethe hybrid analyte level output. For example, in certain embodiments,the analyte monitoring devices include a processor; and memory operablycoupled to the processor, wherein the memory includes instructionsstored therein that, when executed by the processor, cause the processorto generate the hybrid analyte level output—e.g., according to the abovedescribed methods.

In certain embodiments, the analyte monitoring device includes a userinterface to present the hybrid analyte level output. For example, ananalyte monitoring device may include a display and/or speakers tovisually and/or audibly present the hybrid analyte level output to theuser. In certain embodiments, the analyte monitoring device may includeelectronics that couple to an in vivo analyte sensor and communicatewired or wirelessly to a receiver. In some instances, the analytemonitoring device may also include the in vivo analyte sensor. Incertain embodiments, the analyte monitoring device may be a receiverwhich communicates with an electronic unit that couples to an in vivosensor and communicates with the receiver.

In some aspects, analyte monitoring systems are provided that generatethe hybrid analyte level output. For example, in certain embodiments, ananalyte monitoring systems may include an analyte sensor and analytemonitoring device in communication with the analyte sensor. The analytemonitoring device includes a processor, and memory operably coupled tothe processor, wherein the memory includes instructions stored thereinthat, when executed by the processor, cause the processor to generate ahybrid analyte level output—e.g., according to the above describedmethods.

In certain embodiments, the analyte sensor includes sensor electronicsthat couple to an in vivo analyte sensor, and may also include the invivo analyte sensor coupled to the sensor electronics. The analytemonitoring device is a receiver and may include a user interface topresent the hybrid analyte level output. For example, an analytemonitoring device may include a display and/or speakers to visuallyand/or audibly present the hybrid analyte level output to the user.

In some aspects, analyte monitoring systems are provided that include ananalyte sensor and analyte monitoring device in communication with theanalyte sensor, wherein the analyte sensor includes a processor, andmemory operably coupled to the processor, and wherein the analytemonitoring device includes a processor, and memory operably coupled toits processor. For example, the analyte sensor may include sensorelectronics, including the memory and processor, that couple to an invivo analyte sensor, and may also include the in vivo analyte sensorcoupled to the sensor electronics. Furthermore, the analyte monitoringdevice includes a processor, and memory operably coupled to itsprocessor. At least one of the memories include instructions storedtherein that, when executed by the at least one of the processors,causes the at least one processors to generate a hybrid analyte leveloutput—e.g., according to the above described methods.

Some or all of the steps of the methods described above may be performedby the analyte sensor; some or all of the steps of the methods describedabove may be performed by the receiver; and some or all of the steps ofthe methods described above may be performed in various combinations bythe analyte sensor and the receiver.

For example, in one embodiment, for example, the analyte sensor receivessensor data and generates a hybrid analyte level output. The analytesensor then, for instance, communicates the hybrid analyte level outputto the receiver, which may thereafter present the hybrid analyte leveloutput to the user. In one embodiment, for example, the analyte sensorreceives the sensor data and communicates it to the receiver. Thereceiver then receives the sensor data, generates the lag-compensatedanalyte levels, and then generates the hybrid analyte level output. Inone embodiment, for example, the analyte sensor receives the sensordata, generates the lag-compensated analyte levels, and thencommunicates the uncompensated and lag-compensated signals to thereceiver. The receiver then generates the hybrid analyte level output.

In different embodiments, the sensor data from the in vivo sensor may becalibrated or otherwise converted (e.g., with a scaling factor, etc.) atvarious times to provide the appropriate analyte levels. For example, incertain embodiments, the sensor data received is raw sensor that islater calibrated or otherwise converted (e.g., with a scaling factor,etc.). In other embodiments, the sensor data may already be calibratedor otherwise converted to the appropriate analyte levels (e.g., glucoselevels in mg/DL). In certain embodiments, the lag-compensation may beapplied to sensor data that is already calibrated, and thelag-compensated signal generated is at the calibrated analyte level. Incertain embodiments, the lag-compensation may be applied to sensor datathat is raw, and calibration or conversion required at a later time.

Furthermore, in certain embodiments, calibration or conversion to theappropriate levels occurs before the hybrid output analyte level isgenerated, and thus the hybrid output analyte level is at the calibratedanalyte level when generated. Thus, for example, the threshold levelsdiscussed above are relative to the calibrated analyte levels (e.g.,glucose levels in mg/DL). In other embodiments, the hybrid outputanalyte level may be generated from signals that have not beencalibrated or converted, and thus the hybrid output analyte level mayrequire further calibration or conversion before being presented on auser interface. Thus, for example, the threshold levels would berelative to the non-calibrated analyte levels.

For example, in certain embodiments where a receiver receives a hybridoutput analyte level from an on-body analyte sensor, the hybrid outputanalyte level is at the appropriate levels for presenting on a userinterface of the receiver, for example. In yet other embodiments where areceiver receives a hybrid output analyte level from an on-body analytesensor, the hybrid output analyte level is not at the appropriate levelsfor presenting on the user interface of the receiver, and thus iscalibrated or otherwise converted by the receiver before being presentedon the user interface. These concepts are equally applicable to themethods, devices, and systems described herein.

In some aspects, computer systems are provided that generate the hybridanalyte level output. For example, in certain embodiments, a computersystem may include a processor and memory operably coupled to theprocessor. The memory includes instructions stored therein that, whenexecuted by the processor, cause the processor to generate a hybridanalyte level output—e.g., according to the above described methods. Incertain embodiments, the computer system may include a display.

In some aspects, computer-implemented methods of generating a hybridanalyte level output are provided. The computer-implemented methodsinclude receiving sensor data; and generating a hybrid analyte leveloutput including uncompensated analyte levels and lag-compensatedanalyte levels, wherein the uncompensated analyte levels lag in timewith respect to the lag-compensated analyte levels. The hybrid analytelevel output tracks between the uncompensated analyte levels and thelag-compensated analyte levels according to predetermined criteria.

The devices and systems described herein may also include a medicationdelivery device or system, such as an insulin delivery device or system.

It should be understood that techniques introduced above can beimplemented by programmable circuitry programmed or configured bysoftware and/or firmware, or they can be implemented entirely byspecial-purpose “hardwired” circuitry, or in a combination of suchforms. Such special-purpose circuitry (if any) can be in the form of,for example, one or more application-specific integrated circuits(ASICS), programmable logic devices (PLDs), field-programmable gatearrays (FPGAs), etc.

Software or firmware implementing the techniques introduced herein maybe stored on a machine-readable storage medium (also generally referredto herein as computer-readable storage medium or computer-readablemedium) and may be executed by one or more general-purpose orspecial-purpose programmable microprocessors. A “machine-readablemedium”, as the term is used herein, includes any mechanism that canstore information in a form accessible by a machine (a machine may be,for example, a computer, network device, cellular phone, personaldigital assistant (PDA), manufacturing took, any device with one or moreprocessors, etc.). For example, a machine-accessible medium includesrecordable/non-recordable media (e.g., read-only memory (ROM); randomaccess memory (RAM); magnetic disk storage media; optical storage media;flash memory devices; etc.), etc.

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how tomake and use the embodiments of the invention, and are not intended tolimit the scope of what the inventors regard as their invention nor arethey intended to represent that the experiments below are all or theonly experiments performed. Efforts have been made to ensure accuracywith respect to numbers used (e.g., amounts, temperature, etc.) but someexperimental errors and deviations should be accounted for. Unlessindicated otherwise, parts are parts by weight, molecular weight isweight average molecular weight, temperature is in degrees Centigrade,and pressure is at or near atmospheric

1. A method of generating a hybrid analyte level output, comprising:receiving continuous sensor data comprising uncompensated analyte levelsreceived from an in vivo sensor integrated with a drug delivery system,the uncompensated analyte levels comprising interstitial fluid glucoselevels; deriving lag-compensated analyte levels from the uncompensatedanalyte levels using a processor, the lag-compensated analyte levelscomprising estimated blood glucose levels; and generating the hybridanalyte level output comprised of the uncompensated analyte levels andthe lag-compensated analyte levels using the processor, wherein theuncompensated analyte levels lag in time with respect to thelag-compensated analyte levels; wherein the hybrid analyte level outputtracks between the uncompensated analyte levels and the lag-compensatedanalyte levels according to predetermined criteria, the predeterminedcriteria comprising: criteria for tracking the uncompensated analytelevels when selected analyte levels are below a predetermined thresholdand have been rising for at least a predetermined duration of time;criteria for tracking the lag-compensated analyte levels when theselected analyte levels are not below the predetermined threshold orhave not been rising for at least the predetermined duration of time;and wherein the drug delivery system is configured to administer insulinbased on the hybrid analyte level output.
 2. The method of claim 1,wherein the received continuous sensor data comprising uncompensatedanalyte levels is calibrated, thereby deriving lag-compensated analytelevels that are calibrated and generating hybrid analyte level outputthat is calibrated.
 3. The method of claim 1, wherein the selectedanalyte levels comprise at least one selected from the group consistingof most recently derived lag-compensated analyte levels and mostrecently received uncompensated analyte levels.
 4. The method of claim1, wherein the generating comprises: transitioning from theuncompensated analyte levels to the lag-compensated analyte levels andwherein the hybrid analyte level output comprises weighted combinationsof the uncompensated analyte levels and the lag-compensated analytelevels when transitioning from the uncompensated analyte levels to thelag-compensated analyte levels; and/or transitioning from thelag-compensated analyte levels to the uncompensated analyte levels andwherein the hybrid analyte level output comprises weighted combinationsof the uncompensated analyte levels and the lag-compensated analytelevels when transitioning from the lag-compensated analyte levels to theuncompensated analyte levels.
 5. The method of claim 1, wherein thepredetermined criteria further comprises criteria for tracking thelag-compensated analyte levels until the hybrid analyte level outputfalls below a second predetermined threshold, wherein the hybrid analytelevel output tracks a lower of the lag-compensated analyte level and theuncompensated analyte level when the hybrid analyte level output fallsbelow the second predetermined threshold.
 6. The method of claim 1,wherein deriving the lag-compensated analyte levels comprises applying alag compensation filter to the uncompensated analyte levels.
 7. Themethod of claim 1, comprising audibly or visually outputting the hybridanalyte level output on a user interface.
 8. The method of claim 1,comprising audibly or visually outputting the lag-compensated analytelevels on a user interface.
 9. The method of claim 8, further comprisingindicating a low analyte level with the user interface when thelag-compensated analyte levels falls below a predetermined low-enteringthreshold value.
 10. The method of claim 9, comprising: removing theindication of the low analyte level when a predetermined low-exitingthreshold value is exceeded by at least one signal selected from thegroup consisting of the lag-compensated analyte levels, theuncompensated analyte levels, and the hybrid analyte level output. 11.The method of claim 1, wherein the predetermined threshold comprises aglucose value that indicates hypoglycemia.
 12. An analyte monitoringdevice, comprising: a processor; and non-transitory memory operablycoupled to the processor, the non-transitory memory includinginstructions stored therein that, when executed by the processor, causethe processor to: receive continuous sensor data comprisinguncompensated analyte levels received from an in vivo sensor integratedwith a drug delivery system, the uncompensated analyte levels comprisinginterstitial fluid glucose levels; derive lag-compensated analyte levelsfrom the uncompensated analyte levels, the lag-compensated analytelevels comprising estimated blood glucose levels; and generate a hybridanalyte level output comprised of the uncompensated analyte levels andthe lag-compensated analyte levels, wherein the uncompensated analytelevels lag in time with respect to the lag-compensated analyte levels;wherein the hybrid analyte level output tracks between the uncompensatedanalyte levels and the lag-compensated analyte levels according topredetermined criteria, the predetermined criteria comprising: criteriafor tracking the uncompensated analyte levels when selected analytelevels are below a predetermined threshold and have been rising for atleast a predetermined duration of time; criteria for tracking thelag-compensated analyte levels when the selected analyte levels are notbelow the predetermined threshold or have not been rising for at leastthe predetermined duration of time; and wherein the drug delivery systemis configured to administer insulin based on the hybrid analyte leveloutput.
 13. The analyte monitory device of claim 12, wherein thereceived continuous sensor data comprising uncompensated analyte levelsis calibrated, thereby deriving lag-compensated analyte levels that arecalibrated and generating hybrid analyte level output that iscalibrated.
 14. The analyte monitoring device of claim 12, wherein theselected analyte levels comprise at least one selected from the groupconsisting of most recently derived lag-compensated analyte levels andmost recently received uncompensated analyte levels.
 15. The analytemonitoring device of claim 12, wherein the hybrid analyte level outputtransitions from: the uncompensated analyte levels to thelag-compensated analyte levels and comprises weighted combinations ofthe uncompensated analyte levels and the lag-compensated analyte levels;and/or the lag-compensated analyte levels to the uncompensated analytelevels and comprises weighted combinations of the uncompensated analytelevels and the lag-compensated analyte levels.
 16. The analytemonitoring device of claim 12, wherein the predetermined criteriafurther comprises criteria for tracking the lag-compensated analytelevels until the hybrid analyte level output falls below a secondpredetermined threshold, wherein the hybrid analyte level output tracksa lower of the lag-compensated analyte levels and the uncompensatedanalyte levels when the hybrid analyte level output falls below thesecond predetermined threshold.
 17. The analyte monitoring device ofclaim 12, wherein a lag compensation filter is applied to theuncompensated analyte levels to derive the lag-compensated analytelevels.
 18. The analyte monitoring device of claim 12, furthercomprising a user interface, wherein the non-transitory memory includesinstructions stored therein that, when executed by the processor, causethe processor to audibly or visually output the hybrid analyte leveloutput on the user interface of the analyte monitoring device.
 19. Theanalyte monitoring device of claim 12, further comprising a userinterface, wherein the non-transitory memory includes instructionsstored therein that, when executed by the processor, cause the processorto audibly or visually output the lag-compensated analyte levels on theuser interface of the analyte monitoring device.
 20. The analytemonitoring device of claim 19, wherein the non-transitory memory furtherincludes instructions stored therein that, when executed by theprocessor, cause the processor indicating a low analyte level with theuser interface when the lag-compensated analyte levels falls below apredetermined low-entering threshold value.